The rate of Vero Beach and Sebastian homes seriously behind in their mortgage payments jumped into double figures for the month of December compared to a year earlier, an industry watchdog reported Thursday. First American CoreLogic said Vero Beach and Sebastian homeowners more than 90 days behind in mortgage payments jumped from 9.46 percent in December of 2008 to 16.08 percent this past December. The 16.08 percent local figure is still better than the state of Florida, according to CoreLogic, which lists 18.67 percent of homes in the state seriously behind in mortgage payments.The Sebastian-Vero Beach area which CoreLogic monitors also saw an increase in foreclosures in the same timeframe, with the rate of homes in some stage of foreclosure among outstanding mortgage loans increasing from 6.04 percent in December 2008 to 9.68 percent this past December. The foreclosure rate for the state is 11.03 percent in Florida and 3.16 percent nationally.