What is the average mile time for a 45 year old?

I'm a male, age 38. I smoke 30 cigarettes a day. I'm not especially fit, but much better than I was 6 months ago. I can do a mile and half in 11:45, so that's just under 8 mins for a mile. If I was only running one mile I might get it down to 7:30. I've read a lot about this and it seems that 4 mins for a mile is top level athlete standard, 5-6 mins is club runner standard and 7-8 mins is just about respectable for a non-competitive runner in his 30s.