調查日期<br>Date of survey	18 - 29	30+	整體 Overall
23-24/9/1997	7.0 	7.6 	7.4 
28-29/10/1997	6.9 	7.5 	7.3 
8-9/12/1997	6.7 	7.1 	7.0 
3-4/6/1998	6.8 	7.2 	7.1 
21/12/1998	6.9 	7.3 	7.2 
8-9/2/1999	7.1 	7.1 	7.1 
15/4/1999	6.8 	7.3 	7.2 
8/6/1999	6.4 	7.0 	6.8 
6/8/1999	6.9 	7.7 	7.5 
26-27/10/1999	6.9 	7.6 	7.4 
13-15/12/1999	6.6 	7.1 	7.0 
1-2/2/2000	7.1 	7.9 	7.7 
6-7/4/2000	7.3 	7.6 	7.5 
7-8/6/2000	6.9 	7.5 	7.4 
21-25/9/2000	7.3 	7.9 	7.8 
4-12/12/2000	7.0 	7.7 	7.5 
22/3-2/4/2001	7.8 	8.2 	8.1 
1-5/6/2001	7.1 	7.5 	7.4 
13-21/9/2001	7.7 	8.3 	8.1 
7-9/12/2001	7.1 	7.8 	7.6 
12-13/3/2002	7.4 	8.3 	8.1 
4-5/6/2002	7.0 	7.5 	7.4 
2-5/9/2002	7.6 	7.9 	7.8 
13-18/12/2002	6.9 	7.6 	7.4 
1-4/3/2003	7.5 	7.8 	7.8 
13-18/6/2003	7.0 	7.4 	7.3 
10-14/12/2003	7.0 	7.7 	7.5 
7-11/6/2004	6.8 	7.6 	7.5 
6-9/12/2004	7.0 	7.7 	7.5 
6-8/6/2005	6.8 	7.7 	7.6 
9-14/12/2005	7.2 	7.9 	7.7 
13-15/6/2006	7.0 	7.8 	7.7 
6-12/12/2006	7.3 	8.0 	7.8 
8-12/6/2007	7.2 	7.8 	7.7 
11-14/12/2007	7.4 	8.0 	7.9 
11-13/6/2008	7.3 	8.2 	8.0 
9-12/12/2008	6.8 	8.0 	7.8 
8-13/6/2009	7.2 	7.8 	7.7 
8-11/12/2009	7.1 	7.9 	7.8 
9-13/6/2010	6.8 	7.9 	7.6 
13-16/12/2010	6.5 	7.3 	7.1 
21-22/6/2011	6.3 	7.5 	7.2 
12-20/12/2011	6.1 	7.3 	7.0 
13-20/6/2012	5.1 	7.4 	7.0 
14-17/12/2012	6.0 	7.8 	7.5 
10-13/6/2013	4.9 	7.2 	6.8 
9-12/12/2013	5.1 	7.3 	6.9 
6-12/6/2014	5.1 	7.0 	6.7 
10-16/12/2014	4.8 	6.9 	6.5
15-18/6/2015	4.6 	7.2 	6.7
3-7/12/2015	4.9 	7.0 	6.6