Every year beginning July first, each intermediate care facility for individuals with intellectual disabilities must be assessed a quarterly rate per licensed bed as of the first day of each quarter. The quarterly rate may not exceed a rate calculated by the department of health and human services as an annual aggregate of gross revenues as of December thirty-first of the preceding year for all intermediate care facilities for individuals with intellectual disabilities, multiplied by one and one-half percent, and divided by licensed beds as of December thirty-first of the preceding year.