WADE DANIELS Staff Reporter Increased housing demand pushed the number of vacant apartments in the San Fernando Valley in April down by 29.8 percent compared to a year earlier, according to data from the city of Los Angeles Housing Department. Growing numbers of residents, from highly paid entertainment industry workers to minimum-wage-earning laborers, have led to the tightening of the market, according to Katherine Bergh, senior vice president at the Sherman Oaks office of Grubb & Ellis Co. “The entertainment industry is growing and people are renting high-end apartments in places like Studio City,” Bergh said. Bergh added that many recent immigrants, who left their low-rent apartments in the Valley after the 1994 Northridge earthquake, are now moving back. There were 12,768 vacant apartments in the Valley in April, compared to 18,187 a year earlier, according to the Housing Department. There were 689 fewer vacant Valley apartments in April compared to the previous month. In April, the vacancy rate for Valley apartments stood at 6.1 percent, compared to 8.8 percent a year earlier and 6.5 percent a month earlier. Bergh said she expects the market to continue to tighten as long as the Valley’s economy is strong or growing. “A strong economy means more people working and able to afford apartments,” she said. Bergh noted that there is very little construction of new apartment buildings going on in the Valley, which means the number of existing units is changing little as the number of prospective renters rises. The increased demand for apartments is driving up the selling prices of apartment properties. Bergh said the average per-unit sale price of Valley apartments was $45,417 in 1997, a rise of 9.8 percent from the year-earlier figure of $41,356.