Private mortgage insurers saw a significant decline in new business during the first quarter of 2005, but profitability was up for most companies and the industry as a whole, according to a new Inside Mortgage Finance analysis. The volume of new primary MI written during the first three months of 2005 dropped 21.5 percent from the fourth quarter of last year, hitting its lowest level – $51.00 billion – since the first quarter of 2001.…