Data from 2001 to 2010 indicate that the prevalence of asthma in the United States appears to have increased from 7.3% to 8.4%. Healthcare visits per 100 persons with asthma declined in primary care settings during the study period, but asthma-related visits to the emergency room and hospitalizations for the disease remained stable. Children with asthma had lower rates of asthma-associated mortality than adults. African Americans with asthma had higher mortality rates than Caucasians.

Source: CDC.