Something like that will be commercially sensitive, both for the lessor and lessee, and you're unlikely to get anyone volunteering such information, especially for a whole range of aircraft.
In broad terms I'd assume the lease costs would be some fraction of the value of the aircraft that would depreciate according to it's age. An aircraft will have a life of 150 to 200months, give or take, so 0.5-0.75% of the value per month, say, and with the lessor having a business to run it could be over 1% of the value per month.
A B747-400 may have a value of $40million, so $400-500k a month to lease one?
wheat and dairy can screw up your brain