The following data are for Guava Company's retiree health care plan for the current calendar year. Number of employees covered 5 Years employed as of January 1 4 (each) Attribution period 20 years EPBO, January 1 $ 58,000 EPBO, December 31 $ 62,640 Interest rate 8 % Funding and plan assets None What is the interest cost to be included in the current year's postretirement benefit expense