Some studies have shown that use of formula can vary according to the parents' socio-economic status, ethnicity or other characteristics. For example, according to a research conducted in Vancouver, Canada, 82.9% of mothers breastfeed their babies at birth, but the number differed between Caucasians (91.6%) and non-Caucasians (56.8%), with the difference essentially attributed to marital status, education and family income.[14] In the United States, mothers of lower socio-economic status have been found less likely to breastfeed, although this may be partly related to adverse effects of government nutrition supplementation programs that provide subsidies for infant formula.[2]