The top lenders in the U.S. mortgage market threw their production machines into overdrive during the fourth quarter but managed only meager growth in their servicing business, according to a new Inside Mortgage Profitability analysis. As a group, the top 30 mortgage lenders originated a whopping $692.4 billion in new business during the fourth quarter of 2002, up 34.3 percent from the previous three-month period. That represented 80.5 percent of the estimated $860.0 billion