I estimate that for each global hectare of additional resource use in 1996, the Gross World Product grew by about $120. At that time, Robert Zubrin proposed in his book The Case for Mars that an extremely efficient privately funded plan for manned exploration of Mars could carry a price tag of about six billion dollars (or about one billion dollars per astronaut for a crew of six), including development costs. This translates into an equivalent of over eight million hectares per astronaut. Annual operating costs (after development) would be half of this. By comparison, during that year the average world citizen was consuming a little over two hectares. This gives us a good benchmark for the minimum operating cost of sending a person to another world: About two million times what an average person consumes.
We could move less than four thousand people per year to Mars if we used all of the resources the world currently consumes. It would take nearly two million years to move our entire population at that rate.