WASHINGTON, Sept 10 (Reuters) - U.S. wholesale inventory accumulation slowed in July, lagging further behind sales, and it is now taking wholesalers the shortest time in seven years to clear shelves. The Commerce Department said on Friday that wholesale inventories rose 0.6% as estimated last month. Stocks at wholesalers increased 1.2% in June. Wholesale inventories climbed 11.5% in July from a year earlier. Inventories are a key part of gross domestic product. The component of wholesale inventories that goes into the calculation of GDP increased 0.7% in July. Business inventories were depleted in the first half of the year, but shortages amid persistent supply bottlenecks because of the COVID-19 pandemic and recent ports congestion in China are frustrating efforts to replenish stocks. Still, inventory rebuilding is expected to underpin economic growth in the second half of the year. Sales at wholesalers increased 2.0% in July after accelerating 2.3% in June. At July"s sales pace it would take wholesalers 1.20 months to clear shelves, the fewest since July 2014, from 1.22 in June.