The current spot price of WTI Houston Crude Oil Futures, expiring in 1-year, is $43 (per bbl). You can contract storage cost for oil, for one year, at 2% (of the underlying spot price) on a continuously compounded basis. The risk-free rate is 0.5% per annum on a continuously compounded basis. If the current spot price for oil is $40.50, what is the implied convenience yield for this contract?