Year	mm Hg
1980	133.6
1981	133.1
1982	132.5
1983	132.1
1984	131.5
1985	131.1
1986	130.8
1987	130.5
1988	130.3
1989	130.2
1990	130
1991	129.9
1992	129.7
1993	129.6
1994	129.5
1995	129.3
1996	129.2
1997	129.1
1998	129
1999	128.9
2000	128.9
2001	128.8
2002	128.8
2003	128.7
2004	128.6
2005	128.6
2006	128.6
2007	128.6
2008	128.5