The volume of refinance originations may have dropped significantly during the first quarter of 2011, but refi transactions continued to account for a historically high share of new business, according to a new ranking and analysis by Inside Mortgage Finance. Lenders originated an estimated $235 billion in refinance loans during the first three months of this year, which represented 72.3 percent of all single-family mortgage production. That was one of the highest quarterly refi market shares ever, ranking behind the fourth quarter of 2010 and the first two quarters of 2009. Refi production volume was down 40.1 percent from the end of 2010, however... [Includes two data charts]