YEAR | No Smoothing | Lowess (5) | YEAR | No Smoothing | Lowess (5) |
1974 | −0.07 | 0.00 | 1997 | 0.47 | 0.43 |
1975 | −0.01 | 0.02 | 1998 | 0.61 | 0.45 |
1976 | −0.10 | 0.04 | 1999 | 0.39 | 0.48 |
1977 | 0.18 | 0.07 | 2000 | 0.39 | 0.50 |
1978 | 0.07 | 0.12 | 2001 | 0.54 | 0.53 |
1979 | 0.16 | 0.16 | 2002 | 0.63 | 0.55 |
1980 | 0.26 | 0.20 | 2003 | 0.62 | 0.59 |
1981 | 0.32 | 0.21 | 2004 | 0.54 | 0.61 |
1982 | 0.14 | 0.21 | 2005 | 0.68 | 0.62 |
1983 | 0.31 | 0.21 | 2006 | 0.64 | 0.63 |
1984 | 0.15 | 0.21 | 2007 | 0.66 | 0.63 |
1985 | 0.11 | 0.22 | 2008 | 0.54 | 0.64 |
1986 | 0.18 | 0.24 | 2009 | 0.66 | 0.64 |
1987 | 0.32 | 0.27 | 2010 | 0.72 | 0.65 |
1988 | 0.38 | 0.30 | 2011 | 0.61 | 0.66 |
1989 | 0.27 | 0.33 | 2012 | 0.64 | 0.70 |
1990 | 0.45 | 0.33 | 2013 | 0.68 | 0.74 |
1991 | 0.40 | 0.33 | 2014 | 0.75 | 0.78 |
1992 | 0.22 | 0.33 | 2015 | 0.90 | 0.83 |
1993 | 0.23 | 0.33 | 2016 | 1.02 | 0.87 |
1994 | 0.32 | 0.34 | 2017 | 0.92 | 0.91 |
1995 | 0.45 | 0.37 | 2018 | 0.85 | 0.95 |
1996 | 0.33 | 0.40 | 2019 | 0.98 | 0.98 |