WASHINGTON: US private employers hired the fewest number of workers in three years in April, which could raise concerns that a recent sharp slowdown in economic growth was spilling over to labour market. Other data on Wednesday showed a steep decline in the trade deficit in March. While the smaller trade gap could be a potential boost to the weak first-quarter economic growth estimate, the plunge in imports of goods to their lowest level since 2010 hinted at sluggish domestic demand. The ADP National Employment Report showed private payrolls increased 156,000 last month, the smallest gain since April 2013.