An organization or institution that desires exemption under this section must file a written application accompanied by written proof of entitlement for each parcel on or before the first day of April in the year in which the exemption is first requested with the assessors of the municipality in which the property would otherwise be taxable. If granted, the exemption continues in effect until the assessors determine that the organization or institution is no longer qualified. Proof of entitlement must indicate the specific basis upon which exemption is claimed. [2007, c. 627, §20 (AMD).]