Year	mm Hg
1980	131.5
1981	131.1
1982	130.7
1983	130.3
1984	129.8
1985	129.4
1986	129
1987	128.7
1988	128.4
1989	128
1990	127.6
1991	127.3
1992	127.1
1993	126.9
1994	126.8
1995	126.6
1996	126.5
1997	126.5
1998	126.6
1999	126.6
2000	126.7
2001	126.8
2002	126.9
2003	127
2004	127.2
2005	127.4
2006	127.8
2007	128.1
2008	128.5