http://csrankings.org/#/fromyear/2017/toyear/2018/index?ai&v...
Here are approximate numbers (with 2 significant digits) of faculty members/university researchers who published as above in each country/continent:
US 770
Canada 92
Asia (including China) 340
China 240
Europe 280
Australia + New Zealand 86
South America 12
The world excluding the US 810
So the US is still far ahead of other nations/regions, but it now has a bit below 50% of the world's university researchers who recently published in top AI conferences. China as a country is close to Europe as a continent and its number of published university researchers has increased rapidly in recent years.
The number of researchers is not weighted by the number of papers published but this number is useful since it counts how many people are capable of advising graduate students to produce world-class research. Using the number of papers is complicated by how likely highly capable international graduate students would choose to study in each program (in addition to the researcher's capability), i.e. university's reputation would have an additional impact beyond its research capability.