Here is a frequency table summarising an airport's weekly passenger data (thousands) for a sample of weeks over the past three years:

Weekly Passengers (000's)	Frequency
(10, 15]	3
(15, 20]	23
(20, 25]	5
(25, 30]	21

For what fraction of weeks were passenger numbers less than or equal to 15 thousand? Please give your answer to two decimal places, (NOT as a percentage).