1. Suppose today is September 26, and you are considering buying one call option expiring on October 26. You need to estimate the risk-free interest rate for that option. You obtain the following US Treasury bill quota from Wall Street Journal.

Treasury bill bid and ask data are representative over-the-counter quotations as of 3pm Eastern time quoted as a discount to face value. Treasury bill yields are to maturity and based on the asked quote.

Maturity	Bid	Asked	Chg	asked yield
9/13/2018	1,868	1,858	0.010	1,884
9/20/2018	1,878	1,868	-0.013	1.894
9/27/2018	1,875	1,865	-0.010	1,893
10/4/2018	1,938	1,928	-0.008	1,957
10/11/2018	1,968	1,958	-0'005	1,988
10/18/2018	1,995	1,985	-0.007	2,017
10/25/2018	2,015	2,005	-0.010	2,038

Use the information above to find out the risk-free interest rate.