Frequencies for first 10,000 rows of msa variable in nhamcsopd2006 dataset :

                msa or non-msa area |      Freq.     Percent        Cum.
------------------------------------+-----------------------------------
MSA (Metropolitan Statistical Area) |      9,300       93.00       93.00
                            Non-MSA |        700        7.00      100.00
------------------------------------+-----------------------------------
                              Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016