Another collection of data points, these ones the Dutch army from 1985, courtesy orbat85.nl:
1st Division: 12285 men plus artillery, engineer, recon, air defense & MP units attached from I NL Corps.
4th Division: 12353 men plus attachments
5th Division: 12183 men plus attachments.
These are general guidelines, since as
orbat85.nl explains:
"Although 1 (NL) Corps included three divisions, these were not fixed formations as for instance in the British or US Army. During operations Commander, 1 (NL) Corps would allocate brigades and corps level assets to the divisional staffs depending the tactical situation, reallocating them as circumstances required. The three divisional staffs thus were pure tactical headquarters, each commanding between two and five brigades and whatever units they would receive from corps level. The brigades were the main operational elements, designed to be able to operate independently for up to forty-eight hours, each having their own artillery, engineers and logistic support.8 Within this adaptable command structure the brigades were the only permanent formations, retaining their units as much as possible."