Complex sentence: Less than 3% of China's disabled population is in the school-aged demographic, although this statistic is shockingly low, the one child policy contributes to much of the population decreases seen in recent history especially among school-aged children.
Split into simpler sentences: Less than 3% of China's disabled population is in the school-aged demographic. Although this statistic is shockingly low, the one child policy contributes to much of the population decreases seen in recent history especially among school-aged children.