Each agency for which the department of administrative services is charged with providing building maintenance services shall pay to the department an annual assessment of 75 cents per square foot of such space which the agency occupies. The department of administrative services may make transfers from appropriate agency accounts to address such assessments. Collected amounts shall be deposited in the building maintenance fund, which shall be nonlapsing and continually appropriated to the department of administrative services for the purposes of covering costs associated with continuing maintenance of buildings, space, and other property which it is charged with maintaining.