Year	mm Hg
1980	131.4
1981	130.6
1982	129.9
1983	129.1
1984	128.3
1985	127.6
1986	127
1987	126.5
1988	126
1989	125.7
1990	125.3
1991	124.9
1992	124.5
1993	124.2
1994	123.8
1995	123.4
1996	123
1997	122.6
1998	122.2
1999	121.8
2000	121.4
2001	121.1
2002	120.7
2003	120.3
2004	120
2005	119.7
2006	119.3
2007	119
2008	118.7