A new study by Thomson Reuters finds health care costs for employers increased 7.3 percent in 2009, a climb from 6.1 percent 2008.

Analysts at Thomson Reuters are quick to note 2009 was a year for negative inflation: "In a year when inflation was non-existent, employer healthcare costs continued to surge," said Chris Justice, author of the report and director of practice leadership for the Healthcare & Science business of Thomson Reuters, in a released statement. "This analysis puts the real-world healthcare challenges facing employers into perspective. These cost increases have come at a particularly difficult time for U.S. companies."

The nation's overall health care spending, which includes Medicare and Medicaid, grew at 4.8 percent - modest compared to how much employers are paying. And small employers especially are feeling the pinch.

Among employers with less than 5,000 employees, health care costs increased 9.8 percent in 2009, nearly double the 5 percent rate seen in 2008.

Medium-sized employers (5,000 to 50,000 employees) saw cost increases accelerate from 6.5 percent in 2008 to 10 percent in 2009.

Among large companies (more than 50,000 employees) costs rose 5 percent in 2009 -- a decrease from the 5.8 percent recorded in 2008.