調查日期<br>Date of survey	18 - 29	30+	整體 Overall
26-27/8/1997	7.9 	8.0 	8.0 
23-24/9/1997	7.8 	8.3 	8.1 
28-29/10/1997	7.8 	8.1 	8.0 
8-9/12/1997	7.7 	7.8 	7.8 
3-4/6/1998	7.7 	7.6 	7.6 
22-24/6/1998	7.4 	7.6 	7.7 
14/8/1998	7.2 	7.7 	7.7 
29/9/1998	7.4 	7.8 	7.7 
21/12/1998	7.5 	7.8 	7.7 
8-9/2/1999	7.7 	7.5 	7.6 
15/4/1999	7.6 	7.7 	7.7 
8/6/1999	7.0 	7.6 	7.5 
6/8/1999	7.5 	8.0 	7.9 
26-27/10/1999	7.5 	7.7 	7.6 
13-15/12/1999	7.1 	7.6 	7.5 
1-2/2/2000	7.7 	8.1 	8.0 
6-7/4/2000	7.7 	7.7 	7.7 
7-8/6/2000	7.3 	7.7 	7.6 
21-25/9/2000	8.1 	8.2 	8.2 
4-12/12/2000	7.7 	8.0 	7.8 
22/3-2/4/2001	8.1 	8.5 	8.4 
1-5/6/2001	7.7 	7.8 	7.8 
13-21/9/2001	7.9 	8.1 	8.0 
7-9/12/2001	7.5 	7.9 	7.7 
12-13/3/2002	7.9 	8.1 	8.1 
4-5/6/2002	7.6 	7.5 	7.6 
2-5/9/2002	7.8 	8.0 	8.0 
13-18/12/2002	7.5 	7.8 	7.8 
1-4/3/2003	7.5 	8.1 	8.0 
13-18/6/2003	7.6 	7.6 	7.6 
10-14/12/2003	7.4 	7.4 	7.4 
7-11/6/2004	7.3 	7.6 	7.5 
6-9/12/2004	7.6 	7.5 	7.5 
6-8/6/2005	7.7 	7.8 	7.8 
9-14/12/2005	7.7 	8.0 	7.9 
13-15/6/2006	7.5 	7.9 	7.8 
6-12/12/2006	7.8 	8.1 	8.0 
8-12/6/2007	7.7 	8.1 	8.0 
11-14/12/2007	8.0 	8.1 	8.1 
11-13/6/2008	7.7 	7.8 	7.8 
9-12/12/2008	8.1 	7.9 	8.0 
8-13/6/2009	7.9 	7.8 	7.8 
8-11/12/2009	8.0 	8.2 	8.1 
9-13/6/2010	7.5 	8.0 	7.9 
13-16/12/2010	8.6 	8.0 	8.1 
21-22/6/2011	7.3 	7.7 	7.6 
12-20/12/2011	7.9 	8.3 	8.2 
13-20/6/2012	7.9 	8.2 	8.1 
14-17/12/2012	8.5 	8.4 	8.4 
10-13/6/2013	8.2 	8.1 	8.1 
9-12/12/2013	8.2 	7.8 	7.9 
6-12/6/2014	7.9 	8.0 	8.0 
10-16/12/2014	8.3 	8.1 	8.2 
15-18/6/2015	7.7 	8.0 	7.9
3-7/12/2015	7.9 	8.2 	8.1