Year	mm Hg
1980	130
1981	129.9
1982	129.7
1983	129.5
1984	129.3
1985	129.1
1986	128.9
1987	128.8
1988	128.7
1989	128.6
1990	128.5
1991	128.4
1992	128.3
1993	128.2
1994	128.2
1995	128.1
1996	128.1
1997	128.1
1998	128.2
1999	128.2
2000	128.4
2001	128.5
2002	128.8
2003	129
2004	129.3
2005	129.6
2006	130
2007	130.4
2008	130.8