47%.

“In wind generation, no state comes close to Iowa, where last year megawatt-hours we generated from wind equaled 47% of all megawatt-hours sold to our retail customers. Additional wind projects to which we are committed will take that figure to 58% in 2017.”

– Warren Buffett, BRK annual letter 2016

For the full letter – well worth reading, as always – see the BRK website.