Rust Bucket Motor Credit Corporation (RBMCC), a subsidiary of Rust Bucket Motor, offered some securities for sale to the public on March 28, 2,008. Under the terms of the deal, RBMCC promised to repay the owner of one of these securities $82,927 on March 28, 2,031, but investors would receive nothing until then. Investors paid RBMCC $21,165 for each of these securities; so they gave up $21,165 on March 28, 2,008, for the promise of a $82,927 payment in 2,031.

Suppose that, on March 28, 2,017, this securitys price is $45,942. If an investor had purchased it for $21,165 at the offering and sold it on this day, what annual rate of return would she have earned?