Home-sale agreements in the nine-county Indianapolis area spiked 17.2 percent in January compared to the same month a year earlier, suggesting last year's housing recovery continues to gain momentum.

Purchase agreements for existing houses totaled 1,892 in January, up from 1,614 in 2012, with increases in every county except for Boone, Indianapolis-based real estate agency F.C. Tucker Co. Inc. said Friday morning.

Morgan County recorded the strongest gain in pended home sales in January, rising 87.8 percent, followed by Shelby County with a 68.8-percent increase. Marion County rose 12.9 percent, with 830 homes sold; Hamilton County increased 13 percent, with 364 homes sold; and Johnson County gained 21.1 percent, with 155 homes sold.

The inventory of houses for sale continued to slide in January, dropping 16 percent, as buyers snapped up available houses. The region had 10,175 houses for sale, a drop of 1,931 compared to January 2012. Every central Indiana county recorded a decline, but Hamilton County led the way with a 19.6-percent decrease.

Average selling prices also rose, by 5.2 percent to $142,985. But not every county saw gains: Hendricks recorded a 12.6-percent drop, followed by Shelby with a 6.6-percent decline, and Hamilton with a 1.5-percent decrease.

Marion County was the top performer on sale-price gains, rising 12.1 percent to an average of $113,772.