Under a program sponsored by the New Mexico Livestock Board, owners of horses and other live- stock in Grant County can have chips inserted into their animals for $5 in vet fees and $30 for a permit. The state of New Mexico appropriated $840,000 to improve the program of animal inspection and movement control so that officials will be able to track and identify all animals and premises that have had contact with an animal disease within 48 hours of initial diagnosis. If the state receives the permit and vet fees from 500 animal owners per month, how long will it take for the state to recover its investment at an interest rate of 1.5% per quarter compounded monthly?