Excuse me. We'll take that prize.

Here's an interesting chart from Jim Rose's blog.

I don't know why there is "no data" for NZ. From the 2013 census - within the period they analysed -from NZ Stat chart,  "Number of dependent children and total number of children, for one parent families in occupied private dwellings, 2001, 2006, and 2013 Censuses (RC, TA)"  in 2013 =  201,804 out of a total of 671,287. 30 percent. Higher than any other number on the graphic above.

But that would have spoiled the title.