at the start of a file trans-coded from another encoding. While ASCII text encoded using UTF-8 is backward compatible with ASCII, this is not true when Unicode Standard recommendations are ignored and a BOM is added. A BOM can confuse software that isn't prepared for it but can otherwise accept UTF-8, e.g. programming languages that permit non-ASCII bytes in string literals but not at the start of the file. Nevertheless, there was and still is software that always inserts a BOM when writing UTF-8, and refuses to correctly interpret UTF-8 unless the first character is a BOM (or the file only contains ASCII). Adoption Many standards only support UTF-8, e.g. open JSON exchange requires it (without a byte order mark (BOM)). UTF-8 is also the recommendation from the WHATWG for HTML and DOM specifications, and the Internet Mail Consortium recommends that all e‑mail programs be able to display and create mail using UTF-8. The World Wide Web Consortium recommends UTF-8 as the default encoding in XML and HTML (and not just using UTF-8, also declaring it in metadata), "even when all characters are in the ASCII range ... Using non-UTF-8 encodings can have unexpected results". Lots of software has the ability to read/write UTF-8, and for some functions (even in some Microsoft products) UTF-8 is the only option. In some cases (e.g. on Windows) it may though require the user to change options from the normal settings, or may require a BOM (byte order mark) as the first character to read the file. Examples of software supporting UTF-8 include Microsoft Word and Microsoft Excel (2016 and later). Examples of software supporting UTF-8 include Google Drive and LibreOffice. Most databases support UTF-8 (sometimes the only option as with some file formats), including Microsoft's since SQL Server 2019, resulting in 35% speed increase, and "nearly 50% reduction in storage requirements." Microsoft added support for UTF-8 with Windows 10 19H1 to the legacy -A forms of the Windows API, so many functions introduced since Windows Vista only with (the still recommended) -W forms are but missing. UTF-8 has been the most common encoding for the World Wide Web since 2008. , UTF-8 accounts for on average 97.8% (previously up to 98.0%) of all web pages (and 99.1% of top 10,000 pages and 984 of the top 1,000 highest ranked web pages, the next most popular encoding, ISO-8859-1, is used by 15 of those