| Letter | Number of metro stations | Country | % Correct |
|---|---|---|---|
| C | 5365 | China | 99%
|
| U | 1018 | United States | 99%
|
| F | 502 | France | 98%
|
| G | 413 | Germany | 97%
|
| I | 658 | India | 96%
|
| J | 674 | Japan | 96%
|
| R | 338 | Russia | 96%
|
| Q | 37 | Qatar | 95%
|
| D | 39 | Denmark | 93%
|
| V | 49 | Venezuela | 93%
|
| B | 265 | Brazil | 91%
|
| H | 48 | Hungary | 90%
|
| M | 229 | Mexico | 90%
|
| S | 675 | South Korea | 90%
|
| T | 254 | Turkey | 90%
|
| N | 109 | Netherlands | 85%
|
| A | 98 | Austria | 84%
|
| P | 50 | Portugal | 84%
|
| K | 11 | Kazakhstan | 81%
|
| E | 74 | Egypt | 78%
|