I get the gist of what you are saying but I think the wording is imprecise. First China only has stats on official marriages in China, so I'm not sure what "marry out of China" means. Foreign countries won't share stats with China on whether Chinese nationals got married abroad. Second, since marriage legally is concerning joint ownership of properties, the meaning becomes more complicated. A Chinese foreigner couple can choose to register their marriage in 0, 1 or 2 different places, does this impact the statistics?Most Chinese that marry out of China are women marrying to foreign men.
Foreigners that marry into China are more even, maybe even biased towards Chinese men.
Does marry into China mean the first country the couple register their marriage in is in China, as opposed to say getting married in USA then using the US marriage certificate to also register the marriage in China?
The stat that is similar to the one you described I've seen is like foreign groom/bride numbers in China every year, which might be more relevant for our discussions.