Group disability insurers protected about 37 million U.S. workers against long-term disability at the end of the first half of 2006, 3% more than they protected a year earlier.

The number of U.S. workers protected by group short-term disability policies increased 5%, to more than 15 million.

JHA, Portland, Maine, published the revenue growth rates in a summary of results from a survey of 32 major U.S. disability insurers.

JHA, a disability risk management and consulting unit of the Berkshire Hathaway subsidiary, General Re Life Corp., found that premium revenue from new sales of long-term group disability insurance was down 11% and that premium revenue from new sales of short-term group disability was down about 12%.

But the number of LTD cases sold increased 5.5%, to about 23,000, and the number of STD cases sold increased 7.4%, to about 19,000.

Premium revenue from in-force cases rose 5% for LTD coverage, to $4.3 billion, and 6.2% for STD coverage, to $1.5 billion.

Average premium revenue per employee insured increased 2% in the group LTD market, to $233, and held steady at $195 in the group STD market, according to JHA.

UnumProvident Corp., Chattanooga, Tenn., continues to rank first in terms of revenue from in-force group disability cases, but Hartford Life, a unit of Hartford Financial Services Group Inc., Hartford, ranks first in terms of revenue from new LTD and STD sales.

The combination of a drop in an industrywide revenue from new sales and an increase in the number of new cases sold may mean that group disability insurers are selling coverage to smaller employers, according to JHA President Drew King.