Thrift mortgage activity started the year ahead of the pace set in the early going of 2005, but down from the fourth quarter, according to data from the Office of Thrift Supervision. OTS-regulated thrifts reported $142.6 billion in mortgage originations during the first three months of 2006. That was down 13 percent from the fourth quarter of 2005, and up a modest 0.8 from year-ago levels. … [Two data tables included]