Year	mm Hg
1980	129.2
1981	129.4
1982	129.7
1983	130
1984	130.1
1985	130.4
1986	130.5
1987	130.6
1988	130.7
1989	130.9
1990	130.9
1991	130.9
1992	131
1993	131.1
1994	130.9
1995	131.1
1996	131.2
1997	131.4
1998	131.6
1999	131.9
2000	132.2
2001	132.5
2002	132.9
2003	133.3
2004	133.6
2005	133.9
2006	134.3
2007	134.7
2008	135.1