After delivering an outstanding set of results, in line with expectations, housebuilder Persimmon announced it was further accelerating its return of cash to shareholders.Boosted by a solid start to 2015, with the private sales rate per site 5% stronger than the prior year for the first eight weeks, management said a special dividend payment of 95p per share currently planned for 6 July will be paid on 2 April.For 2014, full year revenue rose 23% to £2.6bn and the underlying operating margin increased to 18.4% thanks to an improvement from 17.7% in the first half to 19.0% in the second due to reducing land recoveries, strong development cost control and increasing build productivity.This allowed underlying profit before tax to leap 44% to £475m, with underlying basic earnings per share soaring 49% to 124.5p."We have had an encouraging start to 2015 and experienced a solid opening period to the spring season with current total forward sales of £1.49bn, 5% ahead of the previous year," said chairman Nicholas Wrigley."Despite some uncertainty arising from the General Election in May, the ongoing gradual improvement in the UK economy and increasing mortgage lender support provides a supportive backdrop for the new homes market."The FTSE 100 group said it had enjoyed further "modest" selling price improvement for our private housing sales and had seen a "solid" opening period to the 2015 spring season with average site visitors in line with this time last year, which was 16% ahead of 2013.So far, 60 of the 120 new active sites planned for the first half of 2015 are already open and by 30 June, management aim to be building houses at roughly 400 active outlets, an increase of 7% over the 375 or so sites at the start of the year.Persimmon said the reduction of stamp duty on house purchases, as introduced by the Chancellor in his Autumn Statement last year, is "supporting sentiment" as well as reducing costs for potential house buyers.