By majority of scholars, it would mean you are divorced for the word
I divorce you cannot be utter even in joke. If said so, it counts as one count of divorce (three counts make it irrevocable). Since he has said it three times, that means the divorce is done irrevocably.
While there are many websites which highlights this issues (and are conflicting in some ways), this particular link makes a little bit better sense to me.
It essentially said, if you utter these words
I divorce you in joke, it counts as divorce. But anything else uttered in joke does not count as divorce, e.g 'I am leaving your for ever' will not count as divorce.
This particular link address another such question where you text message wife and say
I divorce you. It says it does NOT count as divorce unless that is his intention. That most likely means he has to confront her and acknowledge that yes he intended it which would count as divorce. An other similar case, if a husband write on paper and give it to wife which says she is divorced, it also does not count as divorce unless he has some kind of verbal acknowledge. The matter is obviously a little confusing.
This matter is actually more complicated if you follow all the Hadith. There are Ahadith which says even single utterance of divorce count as three but in present day of Islam, we don't really follow. I would simply refrain from uttering any such words even in joke or anger on in any case. To highlight the complexity of divorce matter, I would cite a case in India, where the husband divorced his wife in dream and there were confusion if she was divorced or not. She was obviously not divorced in that case.
A point worth noting is if someone commits a sin out of ignorance, that is not counted as sin as such. For example, if you are fasting but do not know the proper ruling and thus do not observe all the rulings properly, that does not count as sin as it is because you were never told and you cannot be made accountable for it. In such case if the husband fall in this category where he did not know an irrevocable divorce can take place in such case, he should get a chance to be with his wife. After all this was not his intentions.
My Reform Take
I am of the view that the right of verbal divorce should be taken from husband and should be managed by legal court. That way there will be no confusion in divorce and everything will be fully intentional and recorded. I know verbal divorce (by intention) is a huge problem in many countries where the husband issues divorce and then retreats because he simply want to have sex and his divorced wife is the only option. That is a far bigger sin. There were always reforms in Islam. This reform is due also.