House flippers across the country pulled in record profits during the first three months of the year, according to a new report from RealtyTrac. The group said that on average flippers grossed $72,450, and that 17,309 single-family homes were flipped, or sold as part of an arms-length sale for the second time within a 12-month period, during the first quarter.

The cities with the highest average flip returns were Baltimore, central Florida and Detroit, but the markets with the highest share of flips Include Memphis, Miami and Tampa.

Flipping activity has slowed to the lowest level since the second quarter 2011, but when the average gross return on investment (ROI) — average gross profit as a percentage of the average original purchase price — was 35.1 percent. In Minnesota, there were just 189 flips or 3.4 percent of all sales. Here's a look at flipping activity by state: