A federal banking regulator said Thursday that first-lien mortgage performance continued to improve in the fourth quarter of 2013. The Office of the Comptroller of the Currency said in a release that 91.8 percent of mortgages were current and performing at the end of the quarter, compared with 91.4 percent at the end of the previous quarter and 89.4 percent a year earlier. The percentage of early-stage delinquencies, mortgages that were 30-59 days past due, was 2.6 percent, down 8.7 percent from a year ago and the lowest level at year's end since reporting began in January 2008. The percentage of mortgages that were seriously delinquent (3.5 percent in the fourth quarte ) decreased 20.7 percent from a year earlier.