Year	Z-score
1997-01-01	3.9801599999999997
1998-01-01	4.1327000000000000
1999-01-01	4.1327000000000000
2000-01-01	3.7975400000000000
2001-01-01	6.2530199999999990
2002-01-01	6.2530199999999990
2003-01-01	6.2530199999999990
2004-01-01	7.2650200000000000
2005-01-01	7.8935900000000000
2006-01-01	7.7721300000000010
2007-01-01	5.9943300000000010
2008-01-01	6.3005600000000000