BEIJING, April 16 (Reuters) - Real estate investment in China rose 25.6% in the first three months of the year from a year earlier, cooling from a 38.3% gain seen in the first two months, official data showed on Friday. Property sales by floor area grew 63.8% year-on-year, down from a 104.9% rise in the first two months of the year, the National Bureau of Statistics (NBS) said in a statement. New construction starts measured by floor area rose 28.2% from a year earlier, compared with 64.3% growth in the January-February period. (Reporting by Liangping Gao and Ryan Woo; Editing by Ana Nicolaci da Costa)