Sales of existing homes plunged by a record amount in September as turmoil in mortgage markets added more problems to a housing industry in its worst slump in 16 years.

The National Association of Realtors reported Wednesday that sales of existing homes fell 8 percent in September, the largest decline to show up in records dating to 1999. The seasonally adjusted annual sales rate of 5.04 million existing homes was also the slowest pace on record.

The weakness in sales translated into further pressure on prices. The median price – the point at which half the homes sold for more and half for less – fell to $211,700 in September, down by 4.2 percent from the sales price a year ago. It marked the 13th time out of the past 14 months that the year-over-year sales price has decreased.

The 8 percent decline in sales was bigger than the 4.5 percent decline that had been expected.

Analysts blamed the bigger-than-expected slump on the turmoil that hit credit markets and mortgage markets in August as worries increased over rising mortgage foreclosures. [MORE]