Existing home sales nationwide reached a nine-year high in 2015, with 3.1 million single-family homes and condominiums sold during the year. That's up 7.5% from 2014, and the best year since 2006, when 3.4 million homes were sold, according to RealtyTrac. What's more, among the 207 metropolitan statistical areas with at least 100 home sales in 2015, 74 reached a nine-year high in sales volume. From the Twin Cities of Minneapolis-St. Paul to Salem, the capitol of Oregon, here's a look at the 10 markets with the biggest year-over-year percent increases in home sales. The data, from RealtyTrac, is based on metropolitan statistical areas with populations above 100,000 and more than 5,000 home sales in 2015.