Of all the people who’ve ever lived, way more than half have died. Human existance, for the sake of measuring when “modern humans” (as we know us) began existing is about 190,000 BCE. Measured from then, about 109 billion humans have lived and died since then.
Considering about 8 billion are alive on the planet today… yeah, way more than half have died.
It's a fact tied in to exponential growth, during one doubling period, as much of whatever you're tracking gets used as the entire history since that exponential growth started. That last bit is the key, human population is an exponential growth thing, but it hasn't been uninterrupted or by a constant factor. There's a long time when we were hunter/gatherers with a stable population and even in more modern ages, epidemics have reduced populations significantly.