Year	mm Hg
1980	131.3
1981	130.7
1982	130.2
1983	129.7
1984	129.2
1985	128.7
1986	128.3
1987	127.9
1988	127.5
1989	127.1
1990	126.8
1991	126.4
1992	126
1993	125.6
1994	125.2
1995	124.7
1996	124.3
1997	123.8
1998	123.4
1999	122.9
2000	122.5
2001	122
2002	121.7
2003	121.3
2004	120.9
2005	120.6
2006	120.2
2007	119.9
2008	119.6