Defaults within commercial mortgage-backed securities dropped 38% in 2011 from the year before, according to Fitch Ratings.

Roughly 950 loans totaling $13.7 billion defaulted, down from nearly 1,500 loans worth $22.1 billion the year before. The annual default rate was 2.4% in 2011, nearly half the 4.1% rate the year before, Fitch said.

The rating agency expects the default rate in 2012 to hit 14%, though the pace should slow despite a spike in March as reported by Trepp this week.

"Overall CMBS default rates are leveling off, though office will continue to lead new defaults in 2012," said Fitch Senior Director Britt Johnson.

For the first time since Fitch began measuring CMBS defaults, mortgages on office buildings led the year, taking more than 38% of all defaults in 2011, followed 20% from both retail and multifamily.

Fitch also showed the 2007 vintage being the vast majority of the problem. More than 88% of defaulted commercial real estate loans in 2011 were originated in 2007.