Year	mm Hg
1980	131.1
1981	130.8
1982	130.5
1983	130.1
1984	129.8
1985	129.5
1986	129.2
1987	128.9
1988	128.6
1989	128.4
1990	128.2
1991	128
1992	127.9
1993	127.7
1994	127.5
1995	127.3
1996	127.1
1997	127
1998	126.9
1999	127
2000	127.1
2001	127.2
2002	127.4
2003	127.5
2004	127.8
2005	128.1
2006	128.4
2007	128.8
2008	129.1