occupancy rate vs percentage

occupancy rate and percentage both are nouns.

Word	Noun	Adjective	Verb	Adverb
occupancy rate	Yes	No	No	No
percentage	Yes	No	No	No

As nouns, percentage is a hypernym of occupancy rate; that is, percentage is a word with a broader meaning than occupancy rate:

occupancy rate: the percentage of all rental units (as in hotels) are occupied or rented at a given time
percentage: a proportion in relation to a whole (which is usually the amount per hundred); ten percent

Other hypernyms of occupancy rate include pct, per centum, percent.

occupancy rate (noun)	percentage (noun)
the percentage of all rental units (as in hotels) are occupied or rented at a given time	assets belonging to or due to or contributed by an individual person or group
	a proportion in relation to a whole (which is usually the amount per hundred); ten percent