BANGKOK, Jan 18 (Reuters) - Data published by the Federation of Thai Industries (FTI): KEY DATA Thai monthly car and truck sales: change y/y pct vehicles Dec -14.4 86,858 Nov -15.3 64,771 Oct -10.7 60,634 Sep +2.7 63,516 Aug +2.6 63,609 Jul -0.4 60,635 Jun +9.5 66,049 May +15.9 66,019 Apr +1.7 54,986 Mar -2.3 72,404 Feb -10.7 57,090 Jan -13.4 51,715 2015 -9.3 799,592 2014 -33.7 881,832 - December's auto sale decline was due to the high base effect as consumers rushed to buy cars before tax changes last year, the FTI said. - In 2016, sales dropped 3.9 percent from a year earlier to 768,788 vehicles, it said. - The FTI has forecast domestic sales at 800,000 cars this year. - Annual domestic auto sales have been weak since May 2013, following the fading effect of a government first-car subsidy scheme, which ended in 2012, when sales jumped 81 percent. - Thailand is a regional vehicle production and export base for the world's top carmakers. (Reporting by Kitiphong Thaichareon; Writing by Orathai Sriring; Editing by Amrutha Gayathri)