Prices for industrial properties in the San Fernando Valley and Ventura County have flattened after climbing by about 90 percent in the years from 2002 to 2006, according to data just released by Colliers International. Prices in the local area averaged $124 per square foot in the first quarter of the year, about at the levels they were a year ago, the report found. Vacancy levels were at 3 percent, and asking rents climbed slightly during the quarter. Lack of available space generally curtailed activity in the industrial market for the quarter, Colliers found.