Year	mm Hg
1980	130.6
1981	130.5
1982	130.3
1983	130.1
1984	130
1985	129.8
1986	129.8
1987	129.8
1988	129.8
1989	129.9
1990	130
1991	130.1
1992	130.2
1993	130.3
1994	130.4
1995	130.5
1996	130.6
1997	130.7
1998	130.8
1999	131
2000	131.3
2001	131.5
2002	131.8
2003	132.1
2004	132.5
2005	132.9
2006	133.3
2007	133.7
2008	134.2