Do not use set analysis, use a calculated dimension and a variable containing the base year.
I would do this:
1 - create a variable vBaseYear
2 - create an input box for the variable
3 - create a chart calculated dimension as this (untested, check the parens):
=If(Year = vBaseYear, 'Y', If(Year = vBaseYear + 1, 'Y+1', If(Year > vBaseYear + 1, 'After', Null())))
This should give you a dimension containing 'Y' for rows pertaining vBaseYear, 'Y+1' for the next one and 'After' for years in the future.
Selecting 'Ignore if value is null' will delete every row associated with years < vBaseYear.