The sex ratio of the different administrative divisions of China has been the subject of academic study because of a high imbalance in births since the 1990s[citation needed] and female infanticide further worsening the imbalanced sex ratios at birth.
Gender ratio for ages 1–4
The figures are from the intercensus survey of 2005, which was carried out in November 2005 on a representative 1% of the total population.[1]