0 1 10 Sample assessments during 2000-W30 2000 30 Sample assessments during 2003-W36 2003 36 Sample assessments during 1991-W20 1991 20 Sample assessments during 1988-W18 1988 18 Sample assessments during 1998-W35 1998 35 Sample assessments during 2006-W32 2006 32 Sample assessments during 1989-W21 1989 21 Sample assessments during 2009-W24 2009 24 Sample assessments during 2001-W34 2001 34