The entertainment industry -- the third largest employer in Los Angeles County -- will see its growth lag significantly behind other industries this year, according to a study by the Los Angeles Economic Development Corporation. The LAEDC blamed labor unrest. The writers' strike, it said, drained $2.5 billion from the county's economy. The agency did not indicate the cost of the production slow-down caused by the impasse between the Screen Actors Guild and the Alliance of Motion Picture and Television Producers.