LZW compression works best for files containing lots of repetitive data. That means that no data is being lost in the compression, unlike a lossy format like JPG. LZW became very widely used when it became part of the GIF image format in 1987. Two commonly-used file formats in which LZV compression is used are the GIF image format served from Web sites and the TIFF image format. It is the algorithm of the widely used Unix file compression utility compress, and is used in the GIF image format. LZW compression became the first widely used universal data.