The Camino Real Landfill was required to install a plastic liner to prevent leachate from migrating into the groundwater. The fill area was 50,000 m2 and the installed liner cost was $8 per m2. In order to recover the investment, the owner charges to unload at the rates of $10 per pickup, $25 per dump truck, and $70 per compactor truck load. The fill area is adequate for 4 years. If the annual trafic is estimated to be 2500 pickup loads, 650 dump-truck loads, and 1200 compactor-truck loads, what rate of return will the landfill owner make on the investment? The rate of return that will be made by the landfill owner is ____% per year.