The ages of the residents of Medicine Lake, Montana, in 2010

Age                 Frequency

0 – 9 ……………       30

10 –19 ……………    28

20 –29 ……………    17

30 –39 ……………    22

40 – 49 ……………   23

50 – 59 ……………   46

60 – 69 ……………   37

70 –79 ……………    18

80 – 89 ……………    4

Approximate the mean of the frequency distribution.