The Set::IntSpan approach is very neat, elegant and maintainable.

However, if you want to roll your own, something like this might do the trick:

>perl -wMstrict -le
"my @yrs = @ARGV ? shift @ARGV : ();
 for my $yr (@ARGV) {
   $yrs[-1] =~ m{ (\d+) \z }xms;
   next if $yr - $1 != 1 and push @yrs, $yr;
   $yrs[-1] =~ s{ (?: - \d+)? \z }{-$yr}xms;
   }
 print join q{, }, @yrs;
"
1992  1994 1995  1997 1998 1999 2000  2002  2004 2005 2006 2007 2008
2008  2007  2007 2008 2009
1992, 1994-1995, 1997-2000, 2002, 2004-2008, 2008, 2007, 2007-2009
[download]

(Note: this does only minimal data validation.)

Update: Fixed original statement  my @yrs = shift @ARGV if @ARGV; creating lexical array because such a creation should not be conditional, only its initialization.