The table below shows the results of a study of the number of eggs per clutch for American robins.

Number of Eggs	2	3	4	5
Frequency	6	29	39	8

The cumulative relative frequency of a clutch size of 4 eggs is found by:

     $\displaystyle {C}{R}{F}=\frac{{{6}+{29}+{39}}}{{{6}+{29}+{39}+{8}}}$ 

Calculate this cumulative relative frequency accurate to three decimal places.