I have panel data (extract shown below). For each subject, I would like to compute a single mean of bp_count over their visits. The number of study visits vary by subject.
Then, I would like to create a new variable containing the mean of bp_count for each subject. Suggestions would be appreciated.

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input float(id visit bp_count)
 7 27 3
 7 18 2
 7 36 2
 7 30 2
 7  2 2
 7 12 3
 7 33 2
 7  9 2
 7 24 3
 7 39 2
 7  1 3
 7 15 3
 7  3 2
 7 42 2
 7  6 2
 7 51 2
 7 21 2
 7 48 2
 7  0 3
 7 45 2
10 33 1
10 24 2
10  3 1
10  6 2
10 21 1
10 27 2
10 36 2
10  2 1
10  1 1
10  0 1
end
Happy holidays,
Al Bothwell