By JENNIFER NETHERBY Staff Reporter San Fernando Valley retail sales are expected to slow in 1999 due to an expected drop in consumer spending both locally and nationwide, according to a report by Marcus & Millichap Real Estate Investment Brokerage Co. The forecast is based on the expectation that jobs in L.A. County will grow 1.6 percent in 1999, compared to a 2.2 percent rate for each of the previous two years. The decline in the growth rate is expected to translate into a slowing in consumer spending. “Retail sales have definitely slowed down, however demand for retail development is high,” said Greg Mills, vice president of investments in the Valley for Marcus & Millichap. “There’s a lack of product right now.” Mills said the effect of a consumer spending slowdown won’t be noticeable in the Valley market for some time. Mills said retail vacancy rates in high-demand areas, such as Ventura Boulevard and Topanga Canyon, are expected to remain stable as bigger retail stores buy up smaller strip malls and redevelop them. The Ventura Boulevard corridor and Glendale/Burbank area saw an average 4 percent retail vacancy rate in 1998. Other Valley areas, such as Van Nuys and North Hollywood, had vacancy rates in the double digits. Retail rental rates are expected to increase by 3 percent, with slightly higher increases in prime locations, according to the report.