I have a list of items ordered by a value representing years left and an value attached for each item. I need to determine if there is an easy method of choosing a range with an average age (say 15 Years in my example) and seeing what the average item value is for that group. At the moment I am manually alering the range until I get to a 15 average (to 2 decimal places). I realise that there may be numerous ranges that might get to that average (the item list is several hundred strong) but I just use trial and error until I hit a solution. This can take a few seconds or can take a longer time to alter the date range to hit the right average. I was wondering if any one can suggest a possible solution?