NEW YORK (Reuters) - A gauge of online labor demand in the United States grew in July compared to a year earlier, but dipped on a monthly basis as the need for employees slowed in the summer months, a private research group said on Friday.

Monster Worldwide Inc, an online careers and recruiting firm, said its employment index was at 144, up 4.3 percent from 138 in July 2010.

Even so, the index dipped 1.4 percent from 146 in June when it was at its highest level in more than 2-1/2 years.

The report saw annual growth in 11 of the 20 industries and 16 of the 23 occupations monitored last month.

Demand was seen particularly in jobs that require specialized skills, such as information technology, engineering and healthcare, Monster said.

"For highly skilled positions, recruitment is pretty strong, and companies are aggressive and even having challenges finding the right people," said Jesse Harriott, a senior vice president at Monster.

Harriott said a month-over-month decline during the summer was typical.

The Monster Employment index is a monthly analysis based on a selection of corporate career sites and job boards. The margin of error is approximately plus or minus 1 percent.

The report was another look at the labor market ahead of the U.S. government's key jobs report due later on Friday. Nonfarm payrolls are expected to have increased 85,000 last month after rising only 18,000 in June.

(Reporting by Leah Schnurr, Editing by Chizu Nomiyama)

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