Answer:
   
   A 1990 [yes, this appears to be the latest survey] National Jewish
   Population Survey of the Council of Jewish Federations (which can be
   found at the [5]North American Jewish Data Bank
   ([6]http://web.gc.cuny.edu/dept/cjstu/na.htm) reports the following:
American Jews:  (TOTAL......5,515,000)
     Born Jews, Consider Judaism their religion.....4,210,000
     Born Jews, Citing no religion..................1,120,000
     Jews by Choice (formerly gentiles)...............185,000

Reform.......................41.4%  "Traditional"*............... 3.2%
Conservative.................40.4%  Reconstructionist............ 1.6%
Orthodox..................... 6.8%  Miscellaneous "Jewish"*...... 1.4%
"Just Jewish"*............... 5.2%

*: self-description, though not a denomination.

   Survey Criteria for the classifications:
   
   Orthodox:
          Emphasizes the binding unchanging character of Jewish law
          
   Conservative:
          Asserts the continuing authority of Jewish law as part of a
          dynamic and developing tradition.
          
   Reform:
          Emphasizes the Jewish prophetic values and accepts Jewish
          practices that it considers relevant for modern times.
          
   Reconstructionism:
          A humanistic approach to Jewish tradition that redefines the
          idea of G-d in humanistic terms.
          
   The [7]Information Please Almanac, at
   [8]http://www.infoplease.com/ipa/A0193644.html, reports that as of
   1998, Jews made up approximately 2% of the population of the United
   States. This is about the same percentage as in 1900, but is lower
   than the percentage in 1970 (3.2%). The top 5 non-Christian religions
   in the United States, according to the Almanac, are as follows:
Adherents       1900      Mid-1970s    Mid-1990s     Mid-1995    (Projected)
                                                                   Mid-2000
Nonreligious   1.00M         11.73M       22.23M       23.39M        24.55M
                1.3%           5.6%         8.7%         8.8%          8.8%

Jews           1.50M          6.70M        5.54M        5.52M         5.50M
                2.0%           3.2%         2.2%         2.1%          2.0%

Muslims        0.01M          0.80M        3.60M        3.77M         3.95M
                0.0%           0.4%         1.4%         1.4%          1.4%

Buddhists      0.03M          0.20M        1.68M        1.86M         2.00M
                0.0%           0.1%         0.7%         0.7%          0.7%

Black Muslim   0.00M          0.20M        1.25M        1.40M         1.65M
                0.0%           0.1%         0.5%         0.5%          0.6%

   As this chart shows, the percentage of Jews in the U.S. is projected
   to be slowly shrinking. For this survey, the count for Jews is based
   on the core Jewish population relating to Judaism, excluding Jewish
   persons professing a different religion but including immigrants from
   the former U.S.S.R., Eastern Europe, Israel, and other areas.