China vs. USA

From a piece in Forbes, a refreshing antidote to declinism: 

By the end of the first half of the 21st century, the American population aged 15 to 64--essentially your economically active cohort--are projected to grow by 42%; China's will shrink by 10%. Comparisons with other competitors are even larger, with the E.U. shrinking by 25%, Korea by 30% and Japan by a remarkable 44%.