person sex age     y
 1    F    8    21.0
 1    F   10    20.0
 1    F   12    21.5
 1    F   14    23.0
 2    F    8    21.0
 2    F   10    21.5
 2    F   12    24.0
 2    F   14    25.5
 3    F    8    20.5
 3    F   10    24.0
 3    F   12    24.5
 3    F   14    26.0
 4    F    8    23.5
 4    F   10    24.5
 4    F   12    25.0
 4    F   14    26.5
 5    F    8    21.5
 5    F   10    23.0
 5    F   12    22.5
 5    F   14    23.5
 6    F    8    20.0
 6    F   10    21.0
 6    F   12    21.0
 6    F   14    22.5
 7    F    8    21.5
 7    F   10    22.5
 7    F   12    23.0
 7    F   14    25.0
 8    F    8    23.0
 8    F   10    23.0
 8    F   12    23.5
 8    F   14    24.0
 9    F    8    20.0
 9    F   10    21.0
 9    F   12    22.0
 9    F   14    21.5
10    F    8    16.5
10    F   10    19.0
10    F   12    19.0
10    F   14    19.5
11    F    8    24.5
11    F   10    25.0
11    F   12    28.0
11    F   14    28.0
12    M    8    26.0
12    M   10    25.0
12    M   12    29.0
12    M   14    31.0
13    M    8    21.5
13    M   10    22.5
13    M   12    23.0
13    M   14    26.5
14    M    8    23.0
14    M   10    22.5
14    M   12    24.0
14    M   14    27.5
15    M    8    25.5
15    M   10    27.5
15    M   12    26.5
15    M   14    27.0
16    M    8    20.0
16    M   10    23.5
16    M   12    22.5
16    M   14    26.0
17    M    8    24.5
17    M   10    25.5
17    M   12    27.0
17    M   14    28.5
18    M    8    22.0
18    M   10    22.0
18    M   12    24.5
18    M   14    26.5
19    M    8    24.0
19    M   10    21.5
19    M   12    24.5
19    M   14    25.5
20    M    8    23.0
20    M   10    20.5
20    M   12    31.0
20    M   14    26.0
21    M    8    27.5
21    M   10    28.0
21    M   12    31.0
21    M   14    31.5
22    M    8    23.0
22    M   10    23.0
22    M   12    23.5
22    M   14    25.0
23    M    8    21.5
23    M   10    23.5
23    M   12    24.0
23    M   14    28.0
24    M    8    17.0
24    M   10    24.5
24    M   12    26.0
24    M   14    29.5
25    M    8    22.5
25    M   10    25.5
25    M   12    25.5
25    M   14    26.0
26    M    8    23.0
26    M   10    24.5
26    M   12    26.0
26    M   14    30.0
27    M    8    22.0
27    M   10    21.5
27    M   12    23.5
27    M   14    25.0