Indicates a length value in a number for pixels or a percentage (number plus
percent sign) for percentage length.
Remarks
The NISO JATS table model parameter entity is used in the same way as the equivalent
parameter entity in the XHTML 1.1 table model. Since this parameter entity was named
in the same way as the XHTML 1.1 Tag Set equivalent, it does not follow
the naming conventions for this Tag Set: it is in mixed not lower case, and the
separator character is a period, not a hyphen.