The recession has put downward pressure on costs, but the steepest declines have been recorded in western states, according to Phoenix-based cost consultant Rider Levett Bucknall (RLB), which compiles cost indexes for 13 cities nationwide. The steepest decline recorded by RLB was for Seattle construction costs, which have fallen 5% during the five quarters between the end of 2009 and the end of 2010. During the same period, the RLB cost index declined 3.6% in Phoenix, 1.5% in Portland, Ore., and 1.2% in Las Vegas. Declines have been moderating. In 2010’s fourth quarter, cost slipped in four western cities as well as in Boston and Nashville. The largest quarterly increase was 0.3 in Washington, D.C.