Data => Variable*[n-variables] Variable => byte*288[variable-name] double*[n-values]
Data follow the Metadata in the legacy binary format, with sources in
the same order (but readers should use the data-offset in
Metadata records, rather than reading sequentially). Each Variable
begins with a variable-name that generally indicates its role
in the pivot table, e.g. “cell”, “cellFormat”,
“dimension0categories”, “dimension0group0”, followed by the
numeric data, one double per datum. A double with the maximum
negative double -DBL_MAX represents the system-missing value
SYSMIS.