Year	mm Hg
1980	134.2
1981	133.8
1982	133.5
1983	133.2
1984	132.9
1985	132.6
1986	132.4
1987	132.2
1988	132
1989	131.8
1990	131.5
1991	131.3
1992	130.9
1993	130.7
1994	130.4
1995	130.1
1996	129.9
1997	129.6
1998	129.3
1999	129
2000	128.8
2001	128.6
2002	128.4
2003	128.2
2004	128
2005	127.8
2006	127.6
2007	127.4
2008	127.2