When I saw this on twitter, it really made me wonder whether the reported statistics had any significance. Based on the numbers reported, I wrote a quick little program to estimate the 95% confidence interval of the percent of CEOs hired internally. Alongside each regions name is the lower and upper cutoff on the 95% confidence interval.
[unix]$ python simulate.py
USA/Canada 0.679 0.859
Western Europe 0.625 0.854
Japan 0.897 1.000
Other mature 0.565 0.826
China 0.710 0.968
Brazil, Russia, India 0.517 0.828