 4
#&gt; 18:     18   rnorm   average         100              0            4
#&gt; 19:     19   rnorm   average         100              0            5
#&gt; 20:     20   rnorm   average         100              0            5
#&gt; 21:     21   rnorm   average         100              1            1
#&gt; 22:     22   rnorm   average         100              1            1
#&gt; 23:     23   rnorm   average         100              1            2
#&gt; 24:     24   rnorm   average         100             