The biggest producer of shiso for the food market is Aichi Prefecture, boasting 3,852 tons, or 37.0% of national production (2008 data). Data for greenhouse production, which is a better indicator of crop yield, gives 3,528 tons for Aichi Prefecture, or 56% share of national production. The difference in percentage is an indicator that in Aichi, the leaves are 90% greenhouse produced, whereas nationwide the ratio is 60:40 in favor of indoors over open fields. In Aichi Prefecture, the city of Toyohashi produces the most shiso in Japan. They are followed in ranking by Namegata, Ibaraki.