* Economic sentiment up by 1.6 points in December * Hits long-term avg first time since July 2011 * Spain and Italy show strong improvement * Business climate broadly unchanged in Dec By Martin Santa BRUSSELS, Jan 9 (Reuters) - Euro zone economic sentiment improved more than expected in December, reaching its long-term average for the first time since July 2011 as all sectors appeared to become more confident about the ongoing economic recovery. Economic sentiment in the 17 countries sharing the euro strengthened by 1.6 points to 100.0 in the ninth straight month of gains, beating economists' expectations, data from the European Commission showed on Thursday. Of the bloc's five largest economies, morale in Spain jumped 4.0 points, 2.3 points in Italy and sentiment in the Netherlands was up by 1.5 points in December. The euro zone's largest economy Germany and the second biggest France saw sentiment improving by 0.3 points in the last month of the last year. Euro zone consumer confidence was up 1.8 points in December as households became more optimistic about future prospects despite high unemployment, stuck at record high of 12.1 percent. The Commission said that employment plans were revised upwards in industry, and the retail and construction sectors and were broadly unchanged in services. A separate data release showed the business climate indicator, which shows the stage in the economic business cycle, edged lower to 0.27 in December from an upwardly revised 0.31 in November, but it still beat market expectations of 0.22.