When absence, under the circumstances described in section 18A:30-1 of this article, exceeds the annual sick leave and the accumulated sick leave, the board of education may pay any such person each day's salary less the pay of a substitute, if a substitute is employed or the estimated cost of the employment of a substitute if none is employed, for such length of time as may be determined by the board of education in each individual case. A day's salary is defined as 1/200 of the annual salary.
N.J.S. § 18A:30-6