Year	mm Hg
1980	136.1
1981	135.4
1982	134.6
1983	134
1984	133.3
1985	132.8
1986	132.2
1987	131.7
1988	131.3
1989	131
1990	130.5
1991	130.1
1992	129.8
1993	129.5
1994	129.2
1995	128.9
1996	128.5
1997	128.1
1998	127.7
1999	127.3
2000	126.9
2001	126.4
2002	126
2003	125.5
2004	125.1
2005	124.6
2006	124.3
2007	123.8
2008	123.4