Frequencies for msr_strt_qtr variable in vwmeasure_dates dataset :

msr_strt_qt |
          r |      Freq.     Percent        Cum.
------------+-----------------------------------
     1Q2010 |          6        7.23        7.23
     1Q2011 |          6        7.23       14.46
     1Q2012 |         11       13.25       27.71
     2Q2011 |         35       42.17       69.88
     3Q2008 |          6        7.23       77.11
     3Q2009 |         18       21.69       98.80
     4Q2010 |          1        1.20      100.00
------------+-----------------------------------
      Total |         83      100.00

by Jean Roth , jroth@nber.org , 16 Nov 2016