According to a recent government report,

... the percentage of Americans of all ages who failed to obtain needed medical care due to cost at some time during the past year, as of January–March 2015:

• All persons: 4.4%, down from 5.3% in 2014
• Hispanic or Latino: 5.7%
• Not Hispanic or Latino, single race, white: 4.1%
•  Not Hispanic or Latino, single race, black: 5.8%

Source: "Early Release of Selected Estimates Based on Data From the January–March 2015 National Health Interview Survey," National Center for Health Statistics (NCHS), Centers for Disease Control and Prevention, September 2015, http://www.cdc.gov/nchs/data/nhis/earlyrelease/earlyrelease201509.pdf