A firm is planning to improve its infrastructure, and currently there are two projects considered for this purpose: Project $x$ and Project Y$.$ Project $x$ has an initial cost of $$101,607\mathrm{.}82$ and is expected to generate annual cash flows of $$10,000$ for the next $15$ years. Project $Y$ has an initial cost of $$45,000\mathrm{.}00$ and is expected to generate annual cash flows of $$4,700$ for the next $15$ years. What is the crossover rate?