Hi

I have a large data set with 9 different balance sheet variables for 57 Companies, over ca. 16 years in weekly intervals.

I want to create a new ID, (The market as a whole) with the average of each variable over the dates.

Code:
  +--------------------------------------+
     |      date   ID   MARKET~N   SHORT_~T |
     |--------------------------------------|
  1. | 14jun2004    8    5.2e+06    9.3e+06 |
  2. | 14jun2004    7     592025      26349 |
  3. | 14jun2004   32    1.7e+07    4.7e+07 |
  4. | 14jun2004   13    2.2e+07    2.1e+07 |
  5. | 14jun2004   56    8.2e+07    2.1e+07 |
     |--------------------------------------|
  6. | 14jun2004   18    8.8e+06    1.2e+08 |
  7. | 14jun2004   31    9.7e+07    1.6e+08 |
  8. | 14jun2004    6    7.9e+06    2.0e+07 |
  9. | 14jun2004   11    1.7e+07    1.4e+07 |
 10. | 14jun2004   43    1.3e+06     202387 |
     +--------------------------------------+
Is it possible?