Mandatory store closures in the U.S. sparked a catastrophic drop in retail sales in March -- and this will worsen in April, according to Forrester Research Inc. More than US$150 billion in U.S. retail sales could disappear in April compared to the same month in 2019, Forrester said in a recent report. That follows the nearly US$100 billion that was lost in March. Meanwhile, e-commerce is gaining: While online sales were 19 per cent of overall sales in March, Forrester estimates this will rise to 25% in April.