accounting labour-labour turnover

A company had 500 worked at the start of a period. During the period,70 workers left the company for various reasons and 46 new workers were employed.

what is the labour turnover rate for the period ( to the nearest %) ?

please correct my calculation :

opening 500
less : left 70
430
add : 46
closing 476

my answer : 46 / 500+476 /2 = 46/488 = 0.094262 x100 = 9%
(I take 46 because is subject to the lower off / the rate should kept as low as possible?)

500-476=24 is total for employed for this question ? my way to find total employed whether is correct?

thank you.