Year	mm Hg
1980	137.7
1981	137.1
1982	136.5
1983	135.8
1984	135.2
1985	134.5
1986	134
1987	133.5
1988	133
1989	132.7
1990	132.4
1991	132.1
1992	131.7
1993	131.4
1994	131.2
1995	130.9
1996	130.6
1997	130.3
1998	130.1
1999	129.9
2000	129.7
2001	129.5
2002	129.2
2003	128.9
2004	128.7
2005	128.5
2006	128.3
2007	128.1
2008	128