Table 5: Proportion of advertisement claims supported or not supported by different kinds of evidence, distinguished by year.

Supported by	2000 (n = 1518)	2004 (n = 1494)	2008 (n = 785)	All years (n = 3797)
High-quality evidence	9%	15%	37%	17%
Low-quality evidence	3%	5%	4%	4%
Experts’ opinion	7%	3%	2%	4%
Reference not available	15%	27%	11%	19%
Not supported by stated evidence	9%	5%	5%	6%
No evidence stated	57%	46%	42%	49%