In some South American countries seven people in ten are type O. In parts of Asia type B is nearly as common as O. Choose a blood type, then fill the hidden ten countries where it is most common from 10th place upward, with ranks 11 to 20 shown as hints. Five boards, five very different maps.

How it works

1. Press START and a ranking board from 1st to 20th appears on the left. Ranks 11 to 20 are shown from the start; ranks 1 to 10 are hidden.
2. On the right are ten shuffled cards: the hidden top-10 countrys. None of them overlaps with the visible ranks 11 to 20, so which countrys are in the top ten is settled; the question is the order.
3. You guess from 10th place upward. When "Who is #10?" appears, tap a card. A correct pick slides into that row on the left and reveals its figure.
4. A wrong pick does not reveal the answer. The card shakes red and you lose one try, leaving three more tries for that rank. Only after four wrong picks is the answer revealed, and the row is marked as missed.
5. Continue through 9th, 8th… up to 1st. Your score is the number of ranks solved plus a miss count, and each row shows on which try you got it. The search box under the results ranks any entry in the full list, even outside the top 20.

Scoring and records

The score is the number of ranks solved, out of ten; wrong picks are counted separately as misses. Between two perfect runs, fewer misses is the better record, and your best is saved in this browser. The visible figures for ranks 11 to 20 are your hints: the 10th-place value must be at least the 11th, so use the lower ranks to judge which country sits near the border. As you climb, fewer cards remain and 1st place is settled by elimination, so the real contest is getting 10th through 2nd right without a miss.

The data: ABO and Rh distribution by country

The figures come from a public compilation of national statistics published by red cross societies, blood services and health ministries. The raw data splits each country into eight groups (O+, A+, B+, AB+, O−, A−, B−, AB−). This quiz adds the positive and negative halves to get the share of types O, A, B and AB, and uses the sum of the four negative groups as a fifth board for Rh-negative blood. Survey years and sample sizes differ between countries, so small decimal differences mean little, but the continental patterns are clear.

Type O dominates the Americas: Ecuador (about 77 percent), Peru (about 71) and Paraguay (about 69) lead, and almost the whole top 20 on that board is in Central or South America, reflecting indigenous ancestry. Type B clusters in Asia, with Thailand (about 37 percent), Laos (about 36) and India (about 34) at the top followed by Pakistan, Bangladesh and Vietnam. Type A exceeds 40 percent in much of Northern and Central Europe and in Japan. Type AB is the rarest everywhere, yet a few countries such as South Korea, Japan and India pass 10 percent.

Why the Rh-negative board is the hardest

Rh-negative blood shows the widest regional spread: around 15 percent in much of Europe, under 1 percent in East Asia. The Basque region of northern Spain is famous for the world's highest rate, so Western European countries such as Spain, the United Kingdom and France sit near the top while Asian and African countries fill the bottom. In the United States roughly 15 percent of people are Rh-negative; in South Korea it is about 0.3 percent, one person in three hundred.

Frequently asked questions

Why start from 10th place?

Almost everyone knows number one, so starting there makes the first question trivial, and with a shrinking pool the last pick would be automatic. Going upward, you tackle the hardest ranks around 10th while the pool is full, and finish by choosing 1st from what is left.

Does a wrong pick reveal the answer?

No. You get up to four picks per rank (one plus three more tries). A wrong card stays in the pool because it may be right for another rank, and the answer is revealed only after four wrong picks.

Is 1st place automatic at the end?

Yes. With one card left, 1st place is settled. That is why the score tops out at ten and records are separated by misses. The real goal is to get 10th through 2nd right without a miss, and the result board shows on which try you solved each rank.

The figure for my country looks different from what I know.

Donor statistics and population surveys differ, and values move a point or two between survey years. This page uses the compilation's figures as published and links the source under the answer table.

Is blood type linked to personality?

This quiz is about distribution statistics only. Blood-type personality theory is a cultural phenomenon popular in Japan and Korea without scientific support. The rankings here come from medical and donation statistics.

Which countries are missing?

Only the 126 countries with a published national figure are included. Very small countries and those without national statistics are not in the list.

How do I share a result?

The share button on the result screen copies your score and board with a link to this page, or opens your device's share sheet.

Related quizzes

• Average Height by Country Quiz — another ranking with strong regional patterns.
• World Population Ranking Quiz — from percentages back to absolute numbers.
• Supplement Interaction Checker — iron and vitamins, the supplements people ask about around blood donation.

Full top 20

As of: Compiled national statistics (2020s) · Source: Wikipedia — Blood type distribution by country

Show the top 20 answer table (spoiler) — Type O

Rank	Name	Value
1	🇪🇨 Ecuador	77.4%
2	🇵🇪 Peru	71.4%
3	🇵🇾 Paraguay	69.0%
4	🇨🇴 Colombia	66.4%
5	🇸🇻 El Salvador	63.0%
6	🇳🇮 Nicaragua	63.0%
7	🇻🇪 Venezuela	62.3%
8	🇲🇽 Mexico	61.8%
9	🇨🇩 DR Congo	60.5%
10	🇭🇳 Honduras	60.2%
11	🇸🇴 Somalia	60.0%
12	🇨🇱 Chile	59.2%
13	🇬🇦 Gabon	58.9%
14	🇬🇭 Ghana	58.3%
15	🇵🇬 Papua New Guinea	57.5%
16	🇮🇸 Iceland	56.0%
17	🇧🇴 Bolivia	55.9%
18	🇮🇪 Ireland	55.0%
19	🇳🇦 Namibia	54.8%
20	🇦🇷 Argentina	54.6%

Show the top 20 answer table (spoiler) — Type A

Rank	Name	Value
1	🇦🇲 Armenia	50.0%
2	🇳🇴 Norway	49.0%
3	🇵🇹 Portugal	46.6%
4	🇲🇹 Malta	45.5%
5	🇫🇷 France	45.0%
6	🇨🇭 Switzerland	45.0%
7	🇩🇰 Denmark	44.0%
8	🇸🇪 Sweden	44.0%
9	🇦🇹 Austria	44.0%
10	🇧🇬 Bulgaria	44.0%
11	🇨🇾 Cyprus	43.8%
12	🇹🇷 Türkiye	43.8%
13	🇱🇮 Liechtenstein	43.5%
14	🇳🇱 Netherlands	43.0%
15	🇪🇸 Spain	43.0%
16	🇩🇪 Germany	43.0%
17	🇱🇺 Luxembourg	43.0%
18	🇧🇦 Bosnia and Herzegovina	43.0%
19	🇷🇴 Romania	43.0%
20	🇨🇦 Canada	42.0%

Show the top 20 answer table (spoiler) — Type B

Rank	Name	Value
1	🇹🇭 Thailand	37.0%
2	🇱🇦 Laos	35.6%
3	🇮🇳 India	34.1%
4	🇧🇩 Bangladesh	33.7%
5	🇵🇰 Pakistan	33.4%
6	🇲🇲 Myanmar	33.0%
7	🇻🇳 Vietnam	31.0%
8	🇰🇵 North Korea	30.3%
9	🇲🇳 Mongolia	30.2%
10	🇨🇳 China	29.1%
11	🇮🇩 Indonesia	29.0%
12	🇧🇫 Burkina Faso	28.6%
13	🇮🇶 Iraq	28.3%
14	🇲🇾 Malaysia	27.5%
15	🇳🇵 Nepal	27.3%
16	🇱🇰 Sri Lanka	27.0%
17	🇰🇷 South Korea	26.8%
18	🇺🇿 Uzbekistan	26.4%
19	🇭🇰 Hong Kong	26.0%
20	🇲🇺 Mauritius	26.0%

Show the top 20 answer table (spoiler) — Type AB

Rank	Name	Value
1	🇰🇷 South Korea	11.5%
2	🇰🇵 North Korea	11.3%
3	🇦🇿 Azerbaijan	10.0%
4	🇯🇵 Japan	9.9%
5	🇺🇿 Uzbekistan	9.8%
6	🇧🇩 Bangladesh	9.8%
7	🇵🇰 Pakistan	9.7%
8	🇭🇺 Hungary	9.0%
9	🇰🇿 Kazakhstan	8.7%
10	🇪🇬 Egypt	8.7%
11	🇨🇳 China	8.6%
12	🇧🇹 Bhutan	8.4%
13	🇮🇶 Iraq	8.3%
14	🇮🇳 India	8.2%
15	🇲🇩 Moldova	8.1%
16	🇧🇾 Belarus	8.0%
17	🇮🇩 Indonesia	8.0%
18	🇵🇱 Poland	8.0%
19	🇮🇱 Israel	8.0%
20	🇧🇬 Bulgaria	8.0%

Show the top 20 answer table (spoiler) — Rh-negative

Rank	Name	Value
1	🇬🇧 United Kingdom	20.0%
2	🇧🇷 Brazil	19.5%
3	🇪🇸 Spain	18.5%
4	🇸🇮 Slovenia	18.0%
5	🇳🇿 New Zealand	17.0%
6	🇱🇧 Lebanon	16.6%
7	🇮🇪 Ireland	16.0%
8	🇦🇺 Australia	16.0%
9	🇩🇰 Denmark	16.0%
10	🇷🇸 Serbia	16.0%
11	🇸🇪 Sweden	16.0%
12	🇭🇺 Hungary	16.0%
13	🇱🇹 Lithuania	15.7%
14	🇧🇪 Belgium	15.5%
15	🇦🇹 Austria	15.4%
16	🇱🇻 Latvia	15.4%
17	🇮🇸 Iceland	15.2%
18	🇫🇷 France	15.1%
19	🇲🇩 Moldova	15.1%
20	🇮🇹 Italy	15.0%