Americans are seeking medical care in greater numbers than ever before with the number of visits growing at three times the rate of population growth, according to government statistics published on Friday.

People made more than 1 billion visits in 2004 to doctors’ offices, emergency rooms and hospital outpatient departments, according to the report from the National Center for Health Statistics.

This is an increase of 31 percent from 10 years before, while the population rose only 11 percent during the same time, according to the center, part of the U.S. Centers for Disease Control and Prevention.

Nearly half of the 1.1 billion visits were to primary care doctors in office-based practices. Another 18 percent were to medical specialists and 16 percent to surgical specialists. Ten percent of visits were to emergency departments.

Medicaid patients, those with no health insurance and charity cases used hospitals more, and waiting times at emergency rooms, which by federal law must take in everyone who comes, increased significantly, the report found.

“The amount of time a patient waits before seeing a physician in the emergency department increased from 38 minutes in 1997 to 47 minutes in 2004,” the CDC said in a statement.

Last week the Institute of Medicine reported that emergency departments were overwhelmed in the United States and called for the federal government to help change the structure of emergency services.

“There was no change in the average time - about 16 minutes - a patient spends face-to-face with a doctor in an office visit,” the report said.

The most common diagnosis was high blood pressure, seen in 42 million visits, the CDC said.

Diagnoses of diabetes rose by 117 percent and diagnoses of spinal disorders rose by 94 percent, according to the statistical survey, which did not examine reasons for the changes.