Statistics of Mother's Age at Delivery, in Yokohama, Japan, 2012
The following shows the statistics of mother's age when she delivered her baby in 2012. These are the statistics of residents in Yokohama, Japan. Most of the mothers were in 30s when she delivered her child. I think it is a common trend in eastern Asia. Yokohama is a big city near Tokyo. In countryside the average age is slightly younger.
Source is Yokohama Municipal Office.