TOKYO, Feb 18 : Japanese exports jumped 16.8 per cent year-on-year in January, up for a fifth straight month, data from the Ministry of Finance showed on Wednesday. The result compared with a 12 per cent increase expected by economists in a Reuters poll. Imports decreased 2.5 per cent in January from a year earlier, versus a 3 per cent increase expected by economists. As a result, the trade balance stood at a deficit of 1.15 trillion yen ($7.50 billion), compared with the forecast of a deficit