The Fuji apple is an apple hybrid developed by growers at the Tohoku Research Station in Fujisaki, Aomori, Japan, in the late 1930s, and brought to market in 1962. It originated as a cross between two American apple varieties—the Red Delicious and old Virginia Ralls Genet (sometimes cited as "Rawls Jennet") apples. According to the US Apple Association website it is one of the fifteen most popular apple cultivars in the United States. It is named for the town of Fujisaki (the location of Tohoku Research Station). Fuji apples are typically round and range from large to very large, averaging 75 mm in diameter. They contain between 9–11% sugars by weight and have a dense flesh that is sweeter and crisper than many other apple cultivars, making them popular with consumers around the world. Fuji apples also have a very long shelf life compared to other apples, even without refrigeration. With refrigeration, Fuji apples can remain fresh for up to a year. In Japan, Fuji apples continue to be an unrivaled best-seller. Japanese consumers prefer the crispy texture and sweetness of Fuji apples (which is somewhat reminiscent of the coveted Nashi pear) almost to the exclusion of other varieties and Japan's apple imports remain low. Aomori Prefecture, home to the Fuji apple, is the best known apple growing region of Japan. Of the roughly 900,000 tons of Japanese apples produced annually, 500,000 tons come from Aomori. Outside Japan the popularity of Fuji apples continues to grow. Fuji apples now account for 80% of China's 20 million tons grown annually. Since their introduction into the U.S. market in the 1980s, Fuji apples have gained popularity with American consumers—as of 2003, Fuji apples ranked number 4 on the US Apple Association's list of most popular apples, only trailing Red Delicious, Golden Delicious, and Gala. Fuji apples are grown in traditional apple-growing states such as Washington, Michigan, New York, and California. Washington State, where more than half of America's apple crop is grown, produces about 135,000 tons of Fuji apples each year, third in volume behind Red Delicious and Golden Delicious varieties.