Sales of existing homes in the nine-county Indianapolis area are off to a strong start in 2012, with the number of sales agreements increasing 13.4 percent in January compared with the same month a year earlier.

Purchase agreements in the area rose to 1,531 last month, 181 more than in January 2011, according to a report released Monday morning by F.C. Tucker Co. Inc., the city’s largest real estate agency.

In January, Marion County saw a 22.7-percent increase in sales agreements from a year earlier, from 596 to 731. Johnson County saw a larger, 26.9-percent bump, as the number of pending sales rose from 93 to 118. Hancock County tallied a 52.2-percent rise, the largest of the nine counties, with 70 sale agreements after 46 in January 2011.

Hamilton and Hendricks counties, however, both had less activity last month than in January 2011. Pending sales in Hamilton dipped 5.3 percent, to 269 from 284, while sales agreements in Hendricks dropped 10.9 percent, to 123 from 138.

F.C. Tucker expects home sales to continue to improve during the first six months of the year, but then to likely slow a bit during the second half as homebuyers take a “wait-and-see approach” to results of the November presidential election, said Jim Litten, president of F.C. Tucker, in a prepared statement.

Available homes for sale in the nine-county region dropped 15.3 percent in January, with 12,120 houses on the market. Marion County’s inventory fell 18.5 percent.

The average sale price of a home in the area declined 3.3 percent in January, to $134,782.