A new Arizona State University report shows home prices in the Phoenix area dropped a record 28 percent in year-over-year sales in September, the worst such decline on record for the Valley of the Sun.

The Arizona State University-Repeat Sales Index also marks another record: the 19th consecutive month of year-over-year declines in home sale prices.

In a bit of good news, though, the report found that the rate of decline in housing prices is slowing in all parts of the metro Phoenix area, except Tempe. Double-digit price drops for Valley home sales began in March, but have since leveled off.

“That good news must be tempered with the realization that the leveling off may stop with average prices down around 30 percent from the prior year,” said Karl Guntermann, a real estate professor at ASU. “It probably will take months for the index and actual home prices to stop declining.”

The ASU-RSI is based on repeat sales and compares the prices of a single house against itself at different points in time, instead of comparing different homes with different quality factors.