Ad spending in total will rise 3.7 percent this year, lower than the earlier forecast of 4.1 percent in December.

Media buyers expect a “minimal” ad expenditure growth of two percent this year, mostly thanks to the Summer Olympics. TV spending, however, will drop at least two percent in 2009 and stay flat in 2010, according to an article posted by TV Week.

ZenithOptimedia pointed out that some advertisers plan to shift ad budgets from broadcast to cable television, due to the Writers Strike.

“Cable is the only television venue that saw a significant increase in ad revenues in 2007, and we continue to project continued growth of six percent for 2008 and five percent growth from 2009 through 2010,” according to a ZenithOptimedia report.

Although ad growth in North America and Western Europe are in decline, in other markets it is up 11.1 percent for 2008, which is higher than the earlier forecast of 10.9 percent. The global total ad growth forecast is 6.5 percent, down from 6.7 percent, TV Week reported.