Year	mm Hg
1980	132.2
1981	132.1
1982	132
1983	131.9
1984	131.8
1985	131.7
1986	131.5
1987	131.4
1988	131.2
1989	131.1
1990	130.9
1991	130.6
1992	130.1
1993	129.8
1994	129.6
1995	129.4
1996	129.2
1997	129
1998	129
1999	129
2000	129
2001	129
2002	129.1
2003	129.1
2004	129.1
2005	129.1
2006	129.2
2007	129.2
2008	129.2