Both Bond Sam and Bond Dave have $8$ percent coupons, make semiannual payments, and are priced at par value. Bond Sam has $2$ years to maturity, whereas Bond Dave has $15$ years to maturity. If interest rates suddenly rise by $4$ percent, what is the percentage change in the price of Bond Sam? If interest rates suddenly rise by $4$ percent, what is the percentage change in the price of Bond Dave? If rates were to suddenly fall by $4$ percent instead, what would the percentage change in the price of Bond Sam be then? If rates were to suddenly fall by $4$ percent instead, what would the percentage change in the price of Bond Dave be then?