相关系=∩830 198811.29.7 19899.710.6 y=0.8455X+2.5349 199010.68.3 0.6899 19918.311.5 199211.58.5 19938.58.9 19948.911.2 199511.216.5 199616.517.5 199717.516.2 199816.218.4 0 10 15 199918.421.6 200021.618.2 200118.217.6 17.6 17.4t Y t-1 Y t 相关系数 ＝ 0.8306 1988 11.2 9.7 1989 9.7 10.6 1990 10.6 8.3 1991 8.3 11.5 1992 11.5 8.5 1993 8.5 8.9 1994 8.9 11.2 1995 11.2 16.5 1996 16.5 17.5 1997 17.5 16.2 1998 16.2 18.4 1999 18.4 21.6 2000 21.6 18.2 2001 18.2 17.6 17.6 17.4