I will give you a rough idea, because the number fluctuates all the time. In Canada, some 23 million individuals fill in an annual income tax return which is also used to calculate benefits for the child tax credit and for the GST tax credit. There are approximately 1.5 million employers and a similar number of corporations in Canada. There are also 2 million or more entities registered for the GST that send us in amounts of money and complete returns varying in frequency depending on the area of activity.
On June 6th, 2006. See this statement in context.