Differences are not significant...
Upon what statistical measure do you make that rather glib remark, prey tell?
"Statistical measure"... Wow.. Trying to impress people huh?
Given that the article is talking about overall average score. The "statistical measure" is of course the mean... And yes we are talking about the variance of the mean scores. Some years it goes up, some years it goes down... But then again the article only looks at one year's difference lol...
I have to confess the hard data analysis that supports this statement wasn't done by me, but it looks sound to me.