The Board of Selectmen this month approved a split property tax rate for the current fiscal year, which began July 1. The town has had a split rate since fiscal 1990, meaning that residential property is taxed at a lower rate than it would be if the town taxed all property at the same rate. Once again this year, owners of commercial real estate will pay 1.31 times more than what they would pay if the town taxed all property at the same rate. This year, the residential tax rate is $13.72 per $1,000 of assessed value, down from $13.92 in fiscal 2012. The commercial and industrial rate is $18.85 for fiscal 2013, down from $19.16 last fiscal year. Although the rates dropped, the average tax bill will rise due to an increase in assessed values. The real estate tax bill for the average single-family home in North Andover, assessed at $478,064, is $6,559 for fiscal 2013, according to state Department of Revenue records, an increase of $209 over last year. In fiscal 2012, the average single-family home was assessed at $456,212 and had a property tax bill of $6,350, state revenue records show.