TOKYO, JAPAN - Japanese wholesale prices dropped by a record 6.6 percent in June from a year earlier, the central bank said Friday.

The fall was steeper than a revised 5.5 percent drop in May and marked the sixth straight month of year-on-year declines, the Bank of Japan said in a preliminary report.

Annual wholesale inflation topped seven percent last July on the back of higher oil and material costs, but has since evaporated.

Month-on-month wholesale prices in June fell 0.3 percent against a revised fall of 0.5 percent in May, extending their losing streak to a 10th straight month, the central bank said.

Japan, the world's second-largest economy, was stuck in a deflationary spiral for years after its asset price bubble burst in the early 1990s, prompting the central bank to slash interest rates to almost zero.