I have the following dataset from years 2000-2010.

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input float(firmid year industry_city nf)
 43753 2002 1  1
 44789 2002 2  3
 23225 2004 2  1
 91277 2002 2  3
 91965 2002 2  3
 44709 2006 2  1
 44789 2002 3  1
 16757 2004 4  1
 13263 2006 5  1
 71803 2006 6  1
 65341 2006 7 16
 91965 2002 7 34
 41700 2002 7 34
 59421 2002 7 34
 22592 2006 7 16
 15534 2003 7  5
 23146 2002 7 34
 91991 2004 7  9
   561 2002 7 34
 65341 2002 7 34
 63793 2002 7 34
 65341 2003 7  5
 65341 2005 7  8
 15534 2004 7  9
135233 2002 7 34
 78489 2006 7 16
 57204 2002 7 34
 88492 2002 7 34
 54662 2004 7  9
nf is the number of firms in each industry-city in a given year.

I want to create a simple table of data description: the mean and median number of firms in any given industry-city in each year. so what i did is:
Code:
egen mean_nf = mean(nf), by(industry_city year)
But I'm looking for something like a summary results from the sum command to export into a descriptive table. This gives me the average number of firms in each specific industry-city each year, while I'm looking for an average for all the industry-city. Do you have suggestions? Thank you.