Table 1: Participants at a Major AI Conference
Regarding the percent of authors of the papers presented at AAAI 2017 vs AAAI 2012, US decreased from 41% to 34% and China increased from 10% to 23%. The third ranked is UK at 5% for both years. It is clear that only two countries have a very large cluster of researchers.
Since many other venues have more researchers and papers presented than AAAI, the actual percentage across all important conferences might vary from the table. However, the conclusion about the dominance of the US and China likely remains true.
Table 2: World's Largest Public Companies and AI Exposure
Among the top 12 public companies by market capitalization as of March 31, 2017, Apple (1st), Alphabet (2nd), Microsoft (3rd), Amazon (4th), Facebook (6th), Tencent (11th), and Alibaba (12th) (7 out of 12) have high AI exposure. 
Berkshire Hathaway (5th), JP Morgan Chase (9th), and Wells Fargo (10th) in finance have rising AI exposure. The table includes Johnson & Johnson (pharmaceuticals) as having rising AI exposure. The only top 12 firm with low AI exposure is Exxon Mobil.
 Note that by the 4th quarter of 2017, Tencent has moved up to 6th and Alibaba to 8th. https://en.wikipedia.org/wiki/List_of_public_corporations_by...