The Valleys are home to around 30% of the Welsh population, although this is declining slowly because of emigration, especially from the Upper Valleys. The area has a relatively high proportion of residents (over 90% in Blaenau Gwent and Merthyr Tydfil) born in Wales. The area has a slightly younger age profile than Wales as a whole, a result of the lower proportion of elderly residents, and higher rates of teenage pregnancies than elsewhere. In 2004 this put the average age in the Valleys 6 months younger than the Welsh average.