BERLIN, Dec 18 - German business confidence rose for an eighth month in December, the influential Ifo economic research institute said on Thursday. Ifo said its western German business climate index rose more than expected to 96.8, from 95.7 in November, led by a jump in the expectations component to the highest in nine years. Economists polled by last week had predicted an increase to 96.5 . The Munich-based think tank, which polls about 7,000 firms each month, said the improvement in optimism was "primarily the result of more favourable expectations." "The renewed improvement in the business climate index in west Germany confirms the expectations of the Ifo institute that the economic recovery has set in and is gaining strength," Ifo President Hans-Werner Sinn said in a statement. "The surveyed sectors that have lagged behind are also beginning to recover," he added. Companies' assessment of current conditions rose slightly to 83.3, from 83.2 in November, Ifo said. Future expectations jumped to 111.0, the highest since November 1994, from 108.7. The institute's index of business confidence for eastern Germany fell to 104.6, from 105.2, as expectations for the future declined and the assessment of current conditions was unchanged.//