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It took humankind 13 years to add its 7 billionth. That’s longer than the 12 years it took to add the 6 billionth—the first time in human history that interval had grown. (The 2 billionth, 3 billionth, 4 billionth, and 5 billionth took 123, 33, 14, and 13 years, respectively.) In other words, the rate of global population growth has slowed. And it’s expected to keep slowing. Indeed, according to experts’ best estimates, the total population of Earth will stop growing within the lifespan of people alive today.