The dome is expanding, the dome is expanding, take cover...

One of the outcomes of the Gardy era has been the phenomenon of the ever expanding Metrodome. What do I mean? Park factor is a stat that is helpful in assessing how much a specific ballpark contributes to the offensive production of a team or player. If the park factor number above 100 is a park good for hitters and below 100 is a park good for pitchers. The "homerdome" has been traditionally regarded as a hitter's park. Here are the Park factors for the dome to date since its inaugural season. I also include its ranking among all ML parks, since 2001

year park factor PF rank (out of 30 parks)

1982 101
1983 105
1984 105
1985 103
1986 107
1987 95
1988 106
1989 106
1990 108
1991 106
1992 101
1993 102
1994 97
1995 101
1996 104
1997 99
1998 99
1999 105
2000 106
2001 102        12
2002 97          3
2003 101         8
2004 104        10
2005 104        14
2006 99         19
2007 92         28
2008 92         30

It is clear that in the later years of the Gardy era, the Metrodome is regarded as a pitcher's park. Did the Dome change? Did the mysterious air currents of a bygone era stop suddenly? Or simply, did the new hitting philosophy installed by Gardenhire & Co., turned the Dome into Shea stadium by turning the Twins into a light hitting team?