Seoul (AFP) - South Korea on Monday trimmed its economic growth forecast for 2015 to 3.8 percent from 4.0 percent as it vowed to continue expansionary policies aimed at spurring domestic consumption.The revised projection comes after the country's central bank this month warned its own 3.9 percent growth forecast would be "difficult" to maintain as domestic demand alternated between positive and negative territories and a weak yen hurt the price competitiveness of South Korean firms against Japanese rivals abroad.The finance ministry said Monday that, in addition to the 2015 growth forecast being lowered, its estimate for this year's economic growth was also revised down to 3.4 percent from 3.7 percent.