References | Sampling period |
( | 1984-1990 |
( | 1981-1990 |
( | 1985-1992 |
( | 1986-1993 |
( | 1987-1996 |
( | 1986-1994 |
( | 1986-1994 |
( | 1981-1997 |
( | 1986-1989 |
( | 1986-1996 |
( | 1990-1998 |
( | 2000-2002 |
( | 1990-2001 |
( | 1994-2001 |
( | 1995-2001 |
( | 1992-2003 |
( | 1982-2004 |
( | 1999-2003 |
( | 1994-2003 |
( | 1991-2003 |
( | 1991-2009 |
( | 1996-2008 |
( | 2000-2008 |
( | 2004-2009 |
( | 2004-2014 |