Preventive health check-ups account for about one in every 12 outpatient visits to doctors, according to Pittsburgh researchers.

About 63.5 million adults had a preventive health or gynecological check-up each year between 2002 and 2004, with an average annual cost of about $7.8 billion.

Of course, the data in the survey was from doctors themselves, who responded with the 12 percent representation. Of the doctors who participated, just under 5,400 patients came in for preventive check-ups and just over 3,000 were in for gynecological exams, out of a total of 181,173 patients.

The most popular preventive exams from the surveyed doctors included mammograms, cholesterol screening and smoking cessation.