4. Contributions Receivable
Contributions receivable at December 31, 2007 and 2006 of approximately $12.5 million and $12.4 million respectively, represent the present value of the estimated future benefit to be received as a beneficiary in a charitable remainder trust. The interest rates used to dis- count the trust receivable to present value range from 3.5 percent to 6.5 percent at December 31, 2007 and 2006, respectively.