Percent of kcals from protein:
All ages 14.7%, males 14.9%, females 14.6% (NHANES 1999-2000)
Source: Wright JD, Wang CY, Kennedy-Stephenson J, Ervin RB. Dietary intake of ten key nutrients for public health, United States: 1999–2000. Advance data from vital and health statistics; no. 334. Hyattsville, Maryland: National Center for Health Statistics. 2003.