Yes, and the answer is a bit over 100 billion, meaning that about 8% of humans who have ever lived are alive today. This is just an estimate, and it’s subject to a decent amount of error, but it’s probably accurate to within 10% or so. Most of those people lived in the last 2000 years or so, and records from that era of human history are good enough to provide at least reasonable estimates. Only a few billion, or about 10% of humans, lived before the development of agriculture.
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