how to print every year in a loop with xslt

[Kmcdzxoz]

My source documents contain two values (years) that define a range. I put them in variables $year1 and $year2. I now need to print to output a -Element for every year in between these two values, including start and end-year. I see a way in creating a loop with recursion, but esp. don't see how to increment the value by one every time. Any ideas?Thanks