*,?) and logical
operations AND (&), OR (|), NOT (!).
Precedence is !, &, |. ! must be the first character on
the mask. Otherwise, it is treated 'as is'.
- for every year
-1998 for years less than or equal to 1998
1992- for years greater than or equal to 1992
1992-1994 for years between 1992 and 1994
1991 for year 1991 only