A group having more power has little to do with numbers. If that was the case the rich would be more numerous than the poor, and India would be the most powerful country in the world.
The "power" of a country, however you define it, lags the population growth. China was the biggest country for decades, its power only really started exploding some 10 or 15 years ago.
That's an incredibly short sighted way of looking at countries. The US was never the country with highest population growth, and right now is also heading into a demographic collapse.