Greece's statistical authority says domestic retail sales dropped eight percent in July compared with a year earlier, highlighting the painful impact of a four-year recession.

The fall was worst in the clothing and footwear sector, where sales were down 18.6 percent compared with July 2011, the authority said in a statement Friday.

July and August are when Greek retailers offer summer sales, which normally boosts turnover.

But according to separate estimates from Greece's national trade confederation, turnover during the two-month sales period dropped 20 percent compared with a year earlier, and a total 36 percent since the summer of 2010.

Greece is surviving on international rescue loans, in return for a punishing austerity program to right its finances. The country's economy is expected to shrink about 7 percent this year.