Highest natural twinning rate (country)

According to Twinning across the Developing World, an international study and global twins database published in 2011, Benin has the highest natural twinning rate in the world, with 27.9 twins per 1,000 births. Natural twinning rate means that there is no intervention with assisted reproductive technologies such as IVF (in vitro fertilization). IVF and other methods have dramatically increased twinning in western nations: in the USA, in 1980, 1 in 60 babies were born twins. More recent studies indicate that the rate is now 1 in 30 – this is a higher rate than 27.9/1000, but the one in Benin is natural, whereas the one in the USA was boosted by medicine.