. describe mv106 mv107 mv133 mv149

              storage   display    value
variable name   type    format     label      variable label
-----------------------------------------------------------------------------------------
mv106           byte    %8.0g      MV106      educational level
mv107           byte    %8.0g      MV107      highest year of education (at level in mv106)
mv133           byte    %8.0g      MV133      total number of years of education
mv149           byte    %8.0g      MV149      educational attainment

mv149 and mv107 are almost exactly the same. The only difference is that mv149 divides primary into incomplete and complete:

. tab mv149 mv106

         educational |              educational level
          attainment | no educat    primary  secondary     higher |     Total
---------------------+--------------------------------------------+----------
        no education |    12,269          0          0          0 |    12,269 
  incomplete primary |         0     11,710          0          0 |    11,710 
incomplete secondary |         0          0     55,807          0 |    55,807 
  complete secondary |         0          0      4,211          0 |     4,211 
              higher |         0          0          0     17,842 |    17,842 
---------------------+--------------------------------------------+----------
               Total |    12,269     11,710     60,018     17,842 |   101,839

mv133 is a recode of mv106 and mv107. The following table gives the mean of mv133 for each combination of mv106 and mv107. (Ignore the "Total" column and row.) 

. tab mv107 mv106, summarize(mv133) means

                Means of total number of years of education

   highest |
   year of |
education |
(at level |       educational level
in mv106) |   primary  secondary     higher |     Total
-----------+---------------------------------+----------
no years  |         0          .          . |         0
         1 |         1          6         13 | 8.5814143
         2 |         2          7         14 | 8.1771985
         3 |         3          8         15 |  10.65447
         4 |         4          9         16 | 8.6599261
         5 |         5         10         17 | 9.5647399
         6 |         .         11         18 | 11.566783
         7 |         .         12         19 | 12.099424
         8 |         .          .         20 |        20
-----------+---------------------------------+----------
     Total | 3.9836038  9.5509347  15.147237 | 9.9378475