Data on the use of burial vaults and liners outside the United States is very difficult to come by, and usage rates are not known. Burial vaults and liners are almost unheard of in China and Japan. Cremation is required in China, and is used in 90 percent of burials in Japan. They are also uncommon in Italy. In modern Italy, burial plots (either below-ground or in wall loculi) are re-used after a period of years, usually 10 to 25. At that time, most of the soft body parts have decomposed, and the bones are removed to an ossuary.