Sweden was among the last EU nations to make the retention a national law, and from what I have read most ISPs are still in the process of developing/negotiating a long-term solution for storing the data. Since they were to pay the entire cost themselves, this should save them quite a lot of money. Especially if you were prepared to believe their estimated implementations costs of one billion SEK.
However for ISP's that already has this implemented it will probably take more job to remove it instead of just letting it be as is.