Year	mm Hg
1980	133.4
1981	133.1
1982	132.8
1983	132.6
1984	132.3
1985	132
1986	131.7
1987	131.5
1988	131.2
1989	130.9
1990	130.6
1991	130.4
1992	130.1
1993	129.7
1994	129.4
1995	129.2
1996	128.9
1997	128.6
1998	128.4
1999	128.2
2000	128.1
2001	128
2002	127.9
2003	127.8
2004	127.7
2005	127.7
2006	127.6
2007	127.5
2008	127.4