Borrowing costs got even cheaper for home buyers and refinancers this week, as mortgage rates continued to descend. The 30-year fixed-rate mortgage averaged 3.66 percent this week, the lowest weekly average since May 23, 2013, Freddie Mac reports in its weekly mortgage market survey. What’s more, the 15-year fixed-rate mortgage dropped below 3 percent, also for the first time since May 2013. http://bit.ly/Why-Everyone-is-Talking-about-Mortgage-Rates