Online job demand in Los Angeles County rebounded in September as openings for technical, healthcare and security professionals rose, according to a survey released Thursday.

Monster Worldwide’s monthly local employment index for Los Angeles County rose to 104 in September from 101 in August and back to its July level. That puts the reading well above September 2005’s score of 99. A reading of 100 is considered baseline.

The local employment index tracks dozens of online hiring sites, including Monster’s own service. Monster began tracking the Los Angeles market in early 2005.

The September survey found that online job availability saw gains in 14 occupational categories, drops in five and no change in three.

Leading the gainers was online job availability in computer and mathematical occupations, which jumped seven points to a high of 106. Online hiring for health care practitioners saw a similar gain; other big gainers were architecture and engineering, protective services, military services and life, physical and social sciences.

On the flip side, online job availability for legal professionals fell three points, while installation, maintenance and repair services fell one point as the residential real estate slowdown took hold.