Year	mm Hg
1980	130.3
1981	130.4
1982	130.5
1983	130.6
1984	130.7
1985	130.8
1986	130.8
1987	130.8
1988	130.8
1989	130.7
1990	130.6
1991	130.5
1992	130.4
1993	130.2
1994	130.1
1995	129.9
1996	129.6
1997	129.4
1998	129.2
1999	129
2000	128.7
2001	128.5
2002	128.3
2003	128.1
2004	127.8
2005	127.6
2006	127.4
2007	127.1
2008	126.9