B?©la Janky's 2006 paper on Gypsies in Hungary, "The Social Position and Fertility of Roma Women," has lots of interesting facts from the big survey of Roma in 2003. For example, the overall Hungarian total fertility rate is 1.3 babies per woman per lifetime, but for Roma women in 2003, it was 3.0.
And Gypsy generation times are considerably shorter:
"Hungarian women today have their first child at the age of 27—28 ... Three in ten Roma women become mothers before they reach the age of 18 and around two-thirds have their first child at the age of 20 at the latest."
Some other interesting facts from Janky:
For more on Gypsies, here's my 2004 VDARE article.