The US economy grew a disappointing 0.7% in the December quarter compared to an expected 0.8% growth rate. This compared to growth of 2.0% in the third quarter and 3.9% in the second quarter. Business spending, weak exports and a drop in inventories were the main culprits. Households were still active albeit cautious given volatile financial markets and unseasonal warm weather that held back some spending. US growth for 2015...