Read this: When Nike took over from Adidas as Arsenal's kit provider in 1994, Arsenal's away colours were again changed to two-tone blue shirts and shorts. Since the advent of the lucrative replica kit market, the away kits have been changed regularly, with Arsenal usually releasing both away and third choice kits. During this period the designs have been either all blue designs, or variations on the traditional yellow and blue, such as the metallic gold and navy strip used in the 2001–02 season, the yellow and dark grey used from 2005 to 2007, and the yellow and maroon of 2010 to 2013. As of 2009, the away kit is changed every season, and the outgoing away kit becomes the third-choice kit if a new home kit is being introduced in the same year.

Since what year has the away kit been changed every year?
What is the answer? (If it cannot be answered, return "unanswerable")
2009