Fannie Mae and Freddie Mac saw a robust 22.3 percent increase in their single-family business during the second quarter of 2015, according to a new Inside Mortgage Finance ranking and analysis. The two government-sponsored enterprises issued a combined $232.36 billion of single-family mortgage-backed securities during the second quarter. It was their strongest quarterly production level since the third quarter of 2013, and it lifted ... [Includes three data charts]