Average home values in the Tampa Bay market have fallen 10.2 percent over the year to $116,900, among the biggest slides in the country, according to online real estate tracker Zillow.com.

Nationally, home values are down 3.8 percent year-over-year, according to Zillow's home value index for May, which is being released Wednesday.

Between April and May, Tampa home values slipped 0.8 percent, compared with a drop of 0.4 percent nationally. From their peak, home values in the Tampa market have fallen 46 percent.

Out of 126 markets tracked by Zillow, 77 saw monthly declines, 37 posted increases and 12 were flat compared with April. For its year-over-year drop, Zillow singled out Tampa as one of the worst performers along with Detroit, Las Vegas, Orlando, Miami and Phoenix.

Zillow chief economist Stan Humphries predicted more pain with expiring tax credits and persistently high unemployment. "The continuing decline in home values has been expected and is what we've been saying is and will be happening until later this year," Humphries wrote in a monthly blog post.