Pulmonologists generated 17.9% more revenue for hospitals in 2015 than they did in 2012, according to a survey by physician recruitment firm Merritt Hawkins.

In 2015, pulmonologists generated $1.19 million in average net revenue for their affiliated hospitals, compared with $1.01 million in 2012, when Merritt Hawkins last conducted its survey of hospital chief financial officers.

Net revenue generated by physicians in all 18 specialties included in the survey averaged $1.56 million in 2015, which was up 7.7% over the $1.45 million generated in 2012. Average revenue for specialists was up 12.8% – going from $1.42 million in 2012 to $1.61 million in 2015 – while revenue generated by primary care physicians dropped 10.5% from $1.56 million in 2012 to $1.4 million in 2015, the survey showed.

Since specialists’ net revenue is at least partly influenced by patient demographics, those who see more patients over age 65 years, including pulmonologists, may “generate a disproportionate number of medical procedures and tests,” and with “over 10,000 Baby Boomers turning 65 every day,” the demand for those specialists is likely to increase, the report noted.

The survey (available for download here) was completed by 74 hospital chief financial officers. Despite the small number, Merritt Hawkins said that the “results are reliable and accurate, in large part because the overall number for average annual revenue generated by all physician specialties for their affiliated hospitals has remained virtually unchanged” over the course of six surveys spanning 14 years.