What percentage of mothers of young children are also working mothers?

A lot!: At least 50%, the numbers vary depending on geographical region and socio-economic status.

Go to...Ygoy.com: Year 2008 -59.5 % of women above 16 years were either working or looking for work in the US. 46.5 % of the total labor force of the US are women. Will go up to 47 % in the year 2016. Working women will increase of 49 % in the total labor force between the year 2006-2016. In USA 61% (8th in the world) 1950-1998.