A new survey of German business leaders found that interest in hiring additional staff has dropped slightly, a potential sign of further trouble for the German economy. The monthly ifo Employment Barometer index, which is based on surveys of business leaders by the influential Munich-based ifo Institute economic research group, fell to 95.5 points in January, down from 96.5 points in December. But a separate forecast from employment agencies compiled by the government-affiliated Institute for Employment Research (IAB) found a more encouraging picture of the labour market. The IAB’s monthly ind…