The percentages matter, but the numbers matter too. Taiwan had nearly a 10 percent surplus of men when Chiang Kai-shek's defeated armies settled there in 1949. Women who were young in the 1950s in Taiwan (I have spoken to many of these about that era) remember fondly that they could be very choosy about whom they married. Many men in that era never did marry. (Taiwan has had tolerated prostitution throughout the postwar period, which presumably is how the unmatched men dealt with being unmatched.) Today, Taiwan is a HUGE destination for young women from poorer countries (there are a lot of poorer countries than Taiwan, notably Vietnam) who are brought in as "mail-order brides" for older men. But for China to do the same, the Communist Party would have to explicitly give up the claim that it eliminated prostitution after "Liberation" in 1949, and the number of women needed to move into China--from countries that themselves often have shortages of women--would be enormous. Absolute numbers matter. It's much more difficult for China to deal with this problem than for any other country, because of the sheer size of the problem.