Year	mm Hg
1980	128.7
1981	128.4
1982	128.2
1983	128
1984	127.7
1985	127.5
1986	127.4
1987	127.3
1988	127.1
1989	126.9
1990	126.7
1991	126.6
1992	126.4
1993	126.2
1994	126
1995	125.8
1996	125.6
1997	125.5
1998	125.3
1999	125.2
2000	125.1
2001	124.9
2002	124.8
2003	124.6
2004	124.5
2005	124.3
2006	124.2
2007	124.1
2008	123.9