The International Mathematical Olympiad (IMO) is an annual sixproblem mathematical olympiad for precollege students younger than 20. The first IMO was held in Romania in 1959. As we will see, eastern Europeans were top performers in the IMO in the earlier years. You can find the summary data analysis in our Jupyter Notebook on GitHub.
It has since been held annually, except in 1980 (what happened in 1980?). More than 100 countries, representing over 90% of the world’s population, send teams of up to six students (under 20 years old) to compete.
Problems cover extremely difficult algebra, precalculus, and branches of mathematics not conventionally covered at school and often not at university level either, such as
– projective and complex geometry
– functional equations
– combinatorics
– number theory (where extensive knowledge of theorems is required).
No calculus is required. Supporters of not requiring calculus claim that this allows “more universality and creates an incentive to find elegant, deceptively simplelooking problems which nevertheless require a certain level of ingenuity”.

Rank 
Country 
Appearance 
Gold 
Silver 
Bronze 
Honorable_Mentions 
0 
1 
China 
32 
147 
33 
6 
0 
1 
2 
United States 
43 
119 
111 
29 
1 
2 
3 
Russia 
26 
92 
52 
12 
0 
3 
4 
Hungary 
57 
81 
160 
95 
10 
4 
5 
Soviet Union 
29 
77 
67 
45 
0 
5 
6 
Romania 
58 
75 
141 
100 
4 
6 
7 
South Korea 
30 
70 
67 
27 
7 
7 
8 
Vietnam 
41 
59 
109 
70 
1 
8 
9 
Bulgaria 
58 
53 
111 
107 
10 
9 
10 
Germany 
40 
49 
98 
75 
11 