非常感谢分享

con！！！！！！！！！！

A question is why just use a time series from 1992 for China only?
From 1992 to 2009 or earlier, the most sample size would be less than 20, then is it a long term? Or is the sample size large enough?
Why did it include earlier times?
Why did it just use a time series and not cross countries data where differences in systems can be very large?