Year	mm Hg
1980	130.3
1981	130.2
1982	130.1
1983	129.9
1984	129.8
1985	129.8
1986	129.7
1987	129.7
1988	129.6
1989	129.4
1990	129.3
1991	129.2
1992	129.1
1993	128.9
1994	128.9
1995	128.8
1996	128.8
1997	128.9
1998	129
1999	129.2
2000	129.4
2001	129.6
2002	129.8
2003	130.1
2004	130.4
2005	130.7
2006	131
2007	131.3
2008	131.6