$3\mathrm{.}17$ Find the equivalent annual worth for the cash flows shown, using an interest rate of $12\%$ per year. Monetary units are $$1000.$

$\backslash$table$[[$Year$,1,2,3,4,5,6,7,8,9],[$Cash Flow, $$,20,20,20,20,60,60,60,60,60]]$