Year	mm Hg
1980	135.2
1981	135.1
1982	134.9
1983	134.7
1984	134.4
1985	134.2
1986	134
1987	133.7
1988	133.5
1989	133.2
1990	132.9
1991	132.5
1992	132.2
1993	131.9
1994	131.6
1995	131.3
1996	131
1997	130.8
1998	130.6
1999	130.3
2000	130.2
2001	130
2002	129.8
2003	129.6
2004	129.5
2005	129.2
2006	129.1
2007	128.9
2008	128.7