Year	mm Hg
1980	132.8
1981	132.8
1982	132.7
1983	132.5
1984	132.3
1985	132.1
1986	131.9
1987	131.6
1988	131.4
1989	131.2
1990	131
1991	130.9
1992	130.7
1993	130.5
1994	130.3
1995	130.1
1996	129.9
1997	129.8
1998	129.6
1999	129.5
2000	129.4
2001	129.4
2002	129.5
2003	129.5
2004	129.7
2005	129.9
2006	130.1
2007	130.4
2008	130.7