nline and offline holiday sales this year will increase 4.1% to $586.1 billion, the NRF says in its annual holiday spending report. NRF’s 2012 holiday spending growth forecast is higher than the 10-year average holiday sales increase of 3.5%, but lower than last year’s growth of 5.6%. The NRF uses factors including consumer credit, disposable personal income, and previous monthly retail sales releases for its holiday retail sales forecast.