Billboard, Hanteo, Gaon, UK Official Charts (sometimes), and sometimes other national charts.
Amazon is a global online shopping service available in the following countries: Australia, Brazil, Canada, China, France, Germany, India, Italy, Japan, Mexico, Netherlands, Singapore, Spain, Turkey, United Arab Emirates, United Kingdom, and the United States of America.
Every region has their own specified payment method, but all of them accept Visa or Mastercard. Amazon Currency is also applicable to purchase in local currency even when purchasing from the international Amazon website.
NOTE: Amazon purchases sometimes count towards the official national chart of a country, and sometimes do not. Before buying, check with your local/regional fanbase to find out if the purchase link is valid for your national chart.