$($Solving for $n$ with non$-$annual periods$)$ Approximately how many years would it take for an investment to grow fourfold if it were invested at $9$ percent compounded weekly? Assume that you invest $$1$ today.

If you invest $$1$ at $9$ percent compounded weekly, about how many years would it take for your investment to grow fourfold to $$4?($Hint$.$ Remember to convert your calculator solution to years.$)$

years $($Round to one decimal place.$)$