1) The biggest thing we noticed about China's statistics is that the population of china only started to get paid more in the 1970s. At the same time people started to get paid more the children per woman went way down and the life expectancy started to slow as well. I have many predictions on why these changes are connected. I think the one child policy had something to do with this, maybe the decrease in children was less costly for the parents and less of a responsibility so they maybe could work more hours gaining more of an income which makes them wealthier in turn raising the income per person. also life expectancy has to come to a slow at some point it couldn't keep rising at the rate it did so that's why I think it slowed down but with modern technology it is still rising and we can never know when its going to stop.
2) China's life expectancy took a hit in 1917 but returned back to normal in the mid 1940s I think this is because of world war 2 China lost 14 million people in the war so this must've what caused the lowerment of the life expectancy at the time the years dipped really low to the age of 22 in 1918 this is outrageous compared to the 77 years china's life expectancy is today, This is a very realistic theory on why the life expectancy took a fall within these periods.
Chinese soldiers from WW ll
3) The child morality rate also dropped tremendously over the past 200 years bust especially when the 1900 started This is because medicines became effective for illnesses and things started to get a lot more sanitary which means less illness is spread around. The but children are more vulnerable to sickness due to them putting everything and anything they can fit in their mouths in their mouths, That meant they got sick a lot but without quality medicine a lot would die so when the medicine and medicinal knowledge became advanced The mortality rate went down.