Good afternoon, I like would to calculate the media of several variables with missing data.

Code:
var1    var2    var3    var4
 40      83       9        1
 43     .02      98       22
 33.5    2       78       3
  1      99       5       .
  .       6      7        .
 56.4    .        1       8
When I generate a new variable, it do not count with the variable with missing values.

Thank you!

Gabriel Ferreira
(Stata 10.1 SE)