What is the $20-$year Maturity Risk Premium $($rmp$)?$

Years Face Coupon Market

Security Rating Maturity Value Rate Price

Treasury $1$$$1,0000\mathrm{.}00\%$$$966\mathrm{.}66$

Treasury $3$$$1,0002\mathrm{.}00\%$$$939\mathrm{.}06$

Treasury $5$$$1,0004\mathrm{.}40\%$$$932\mathrm{.}42$

Treasury $10$$$1,0007\mathrm{.}20\%$$$1,007\mathrm{.}12$

Treasury $20$$$1,0006\mathrm{.}60\%$$$908\mathrm{.}25$

Corp A A $5$$$1,0008\mathrm{.}10\%$$$1,000\mathrm{.}00$

Corp B BB $10$$$1,0007\mathrm{.}90\%$$$859\mathrm{.}88$

Corp C AA $20$$$1,0008\mathrm{.}20\%$$$972\mathrm{.}22$