Year	mm Hg
1980	131.6
1981	131.4
1982	131.3
1983	131
1984	130.7
1985	130.4
1986	130.1
1987	129.7
1988	129.4
1989	129.2
1990	128.9
1991	128.7
1992	128.6
1993	128.4
1994	128.4
1995	128.3
1996	128.3
1997	128.3
1998	128.4
1999	128.5
2000	128.6
2001	128.8
2002	129
2003	129.3
2004	129.6
2005	129.9
2006	130.3
2007	130.6
2008	131