Answer:
   
   According to the 1993-1994 yearbook of the Union for Reform Judaism,
   there are 853 member congregations, with a total "member unit"
   membership of 302,193 member units. The term "member units" refers to
   the unit that joins a synagogue: a family, a single individual, a gay
   couple. There are also numerous congregations that are Reform but are
   not affiliated with URJ. Some of these are quite large (such as Steven
   S. Wise Congregation in Los Angeles, with over 2,000 member units).
   The breakdown, according to the yearbook, is as follows:
   
        Region                          Congregations           Members
        Canada                          22                        8,252
        Great Lakes                     57                       22,785
        Mid Atlantic                    62                       20,289
        Midwest                         65                       23,401
        New Jersey/W. Hudson            58                       20,829
        New York                        94                       36,122
        Northeast                       78                       26,605
        Northeast Lakes                 69                       23,660
        Northern California             40                       15,137
        Pacific Northwest               18                        5,002
        Pacific Southwest               73                       32,257
        Pennsylvania                    55                       19,721
        Southeast                       85                       28,397
        Southwest                       77                       19,736
        TOTAL                          853                      302,193

   To give an idea of trends, in 1982-1983, the congregational membership
   was 269,406--that's 12% growth over ten years. There were 773 member
   congregations in 1982-1983, giving 10% growth in the number of Reform
   congregations.

Some parts © 2009 Advameg, Inc.