(MarketWatch) -- Thai stocks were sharply lower in afternoon trading Monday after official data released earlier in the day showed the nation's economy unexpectedly contracted 0.2% in the three months ended June 30 from the preceding quarter. The country's gross domestic product for the second quarter was estimated to have a growth of 0.4% in a Dow Jones Newswires poll of economists. The benchmark SET Index, one of the few Asian benchmark indexes to remain in positive territory in the year to date, was down 1.5% at 1,053.06 in the afternoon. The performance came in generally downbeat markets amid global economic worries.