%Length.datatype; Length Datatype
Indicates a length value in a number for pixels or a percentage (number plus percent sign) for percentage length.
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.
<!ENTITY % Length.datatype "CDATA" >