Year	mm Hg
1980	130
1981	129.9
1982	129.7
1983	129.6
1984	129.4
1985	129.4
1986	129.3
1987	129.3
1988	129.4
1989	129.5
1990	129.5
1991	129.7
1992	129.8
1993	129.9
1994	130.1
1995	130.2
1996	130.4
1997	130.6
1998	130.7
1999	130.8
2000	131
2001	131.3
2002	131.4
2003	131.6
2004	131.7
2005	131.8
2006	131.9
2007	132
2008	132.1