a Race categories have been changed since 2001. Data for 2001 and later years may not be comparable to data from previous years.
b Negative/poor refers to household incomes below the Federal poverty line; near poor/low, the poverty line to just below 200 percent of the poverty line; middle, 200 percent to just below 400 percent of the poverty line; and high, 400 percent of the poverty line and over.
Key: AI/AN: American Indian or Alaska Native; NHOPI: Native Hawaiian or Other Pacific Islander; SE: standard error.
Source: Centers for Disease Control and Prevention, National Center for Health Statistics, National Immunization Survey.