As an AI language model, I don't have access to real-time data. However, the T5018 form is used by businesses in Canada to report payments made to subcontractors or independent contractors for construction services. The number of people who fill out the T5018 form each year would depend on the number of businesses that engage in subcontracting or construction services.
Considering the size of the construction industry in Canada, which includes a significant number of subcontractors, it can be assumed that a substantial number of businesses would be required to file the T5018 form. To get an accurate number, you may need to refer to statistics or reports from the Canada Revenue Agency (CRA) or other relevant sources.