Simpletable attribute group
The simpletable attribute group includes several attributes that are defined on the
         <simpletable> element and <simpletable>
         specializations. These attributes are not defined for the OASIS exchange table
         (<table>).
      
      - @keycol
 - Defines the column that can contains headings for each row. No value indicates no key column. When present, the numerical value causes the specified column to be treated as a vertical header.
 - @relcolwidth
 - Specifies
                     the width of each column in relationship to the width of the other columns. The value
                     is
                     a space separated list of relative column widths; each column width is specified as
                     a
                     positive integer or decimal number followed by an asterisk character. 
                     
For example, the value
relcolwidth="1* 2* 3*"gives a total of 6 units across three columns. The relative widths are 1/6, 2/6, and 3/6 (16.7%, 33.3%, and 50%). Similarly, the valuerelcolwidth="90* 150*"causes relative widths of 90/240 and 150/240 (37.5% and 62.5%).