Why is your total world population significantly lower than the actual population?

The total world population that Ethnologue reports is the sum of the total populations of L1 speakers of the living languages. Those population numbers come from a variety of sources and from significantly different points in time. In addition, the Ethnologue lacks population estimates for about 4% of the world's languages and also does not automatically extrapolate population estimates to the current year, but waits for reports from reliable sources. As a result our world population count varies considerably from current census estimates.