I looked in the [Corpus of Contemporary American English][1] (COCA), and the [British National Corpus][2] (BNC), and found this data:

COCA:

    1		 JUDGMENT	15116
    2		 JUDGEMENT	584

Ratio in American usage: 25 to 1 in favor of *judgment*

BNC:

    1		 JUDGMENT	3220
    2		 JUDGEMENT	2441

Ratio in British usage: 1.3 to 1 in favor of *judgment*


So, it does appear that while *judgment* is more common in both British and American English, *judgement* enjoys a substantial percentage of usage in British English, but much less in American English.

**Addendum**: per ShreevatsaR’s suggestion, I searched the BNC again, this time excluding all the spoken sections (“S_*”) as well as the two written legal sections: “W_nonac_law”, “W_ac_law_edu”, and got these results

    1		 JUDGEMENT	2053
    2		 JUDGMENT	1317

We do now find the numbers inverted: the ratio of *judgment* to *judgement* is just 0.64. Although many of the examples remaining of *judgment* are in fact in a legal context anyway, we do find, though, that the spelling *judgment* nevertheless enjoys considerable usage in non-legal contexts. Here are a few examples: 

* “Efficiency at work is decreased and **judgment** impaired, with possible serious results.”
* “There I had him as a charming, affectionate colleague of mature **judgment**.”
* “It is not pleasant for a human being to pass **judgment** on another and say that he is evil through and through without any redeeming features”
* “**Judgment** of humorous writing is even more subjective than with any other kind.”


  [1]: http://www.americancorpus.org/
  [2]: http://corpus.byu.edu/bnc/