Counting Yourself In... Again?

I'm probably the only person in Canada who thinks about this stuff, but is it just me or is the Census a colosal waste of government money? Every five years the government requires Canadians by law to fill out this form, but is it really necessary. The truth is no. Think about it. All that information is already logged somewhere in the vast servers of the government's computer library. Got a birth cirtificat or immigration landing papers? They've got that info too including country of origin. Tax forms list your income, who you work for, and how many people live in your home. They already know where you live or else the package wouln't reach your house. Other stuff that they sometimes ask such as ethnicity is really none of their business, although they can usually guess by name or examining country of origin on immigration papers. Education can be obtained by looking through school board records. The government already has all the information they need, and if lazy civil servants did some digging it could be obtained far easier than making citizens fill out more forms. If they already have everything they need to know, what's the point of asking again?