XLS is the most popular format for storing table data. It is native Microsoft Excel format with data stored in numbered cells that form columns and rows. The top line and left column of each table contains numbering of each cell that can contain either static or dynamic data that is calculated from formulas. XLS features powerful calculation and charts-building options, as well as rich text formatting. XLS is compatible with numerous table editors such as Calc, PlanMaker, OpenOffice, etc.