For full context: http://www3.nhk.or.jp/news/easy/k10011218521000/k10011218521000.html
The sentence in question: 去年１月から１２月までより多くて、今まででいちばん多くなりました。
I always had my issues with より. I think I know what the sentence tells me contentwise, but I can't figure out a proper translation without feeling rather uncomfortable. I used this guide to refresh my knowledge about comparisons with より and also used their literal way of interpreting より. http://www.guidetojapanese.org/learn/grammar/comparison#Using_for_comparisons-2
Here's my attempt at literal translation: "As opposed to last year (=from last years first month to last month), (the tourists) being many, out of (all the years?) until now they/it became the (having) most (tourists (year))."
So, since it is rather obvious from the context that this year has broken the record in tourists/p.a., I think that 今までで refers to "(out of) all years until now" and therefore puts all those years into comparison with 去年去年１月から１２月 (="this year").
However, coordinating these 2 quite big arguments on both sides of より, I feel like I'm missing out on something when constructing a translation which basically just says: "This years tourists were more than any other years tourists.", when there is a phrase like 去年去年１月から１２月 expressing "this year" and two occurences of "many" (=多きい/多く) representing the tourists. The latter also gave me some trouble in analysing the components of 今まででいちばん多くなりました. I'm still not entirely sure which way I have to parse this: Is 多く part of the object in "became the year (having) most (tourists)" or is it it part of the subject "most tourists in "they became the most tourists out of all years". I have a tendency towards the first version, since 今までで in this context suggests that "year" could be the subject of なる here, at least in my eyes.
But whatever, while I think that I got the content of the sentence right, I definitely need some help with the grammar...^^