In the original Ken's message, Ken did mention that because the survey was done before Ji-Woo's visit to Japan. If it's done by now, the % of the question of "Do you know Winter Sonata" should be nealy 100%.

Personally I was surprised to know there were almost 9800 subjects in the survey. However, the ratio between man and woman was not balanced. I guess if there were more woman subjects in the survey, then the % of the question of "Have you watched it" will be higher in the woman's category. It's an exciting evidence to know that Ji-Woo is liked by many Japanese men and women.