It went from 0.2/100k to 0.8/100k. In aggregate, that's 800 people? I wonder how much of that is due to improved reporting given the lapse of the one-child policy, though.
Suicides averaged over all age groups declined by 5% in the same period, so it can't just be better reporting. Also that's an aggregate increase of about 6000, not 800.
Better reporting of children in particular because of the lapse of the one-child policy? For a decent amount of time China had "ghost children" that weren't reported to the government (though you'll find no reports on this from Western media, it's a pretty well-established truth in some Chinese circles).