Tabular information should always be presented using a table
that preserves relationships within the information even when users cannot see the table or the presentation format is changed. Information is considered tabular when logical relationships among text, numbers, images, or other data exist in two dimensions (vertical and horizontal). These relationships are represented in columns and rows, and the columns and rows must be recognizable in order for the logical relationships to be perceived.
More Information in the WCAG 2.0 Guidelines
H39: Using caption elements to associate data table captions with data tables
H43: Using id and headers attributes to associate data cells with header cells in data tables
H51: Using table markup to present tabular information
H63: Using the scope attribute to associate header cells and data cells in data tables
H73: Using the summary attribute of the table element to give an overview of data tables