December 6 (SeeNews) - Bulgaria's annual economic growth slowed down to 3.4% in the third quarter, compared to a revised 3.6% year-on-year increase in the previous quarter, the National Statistics Office (NSI) said on Tuesday citing preliminary data. GDP growth was driven mainly by exports, which expanded by an annual 9.5% in the third quarter following an annual increase of 4.5% in the previous quarter, the NSI said in a quarterly GDP report.