The human species has topped 8 billion, with longer lifespans offsetting fewer births, but world population growth continues a long-term trend of slowing down, the US Census Bureau said Thursday.

The bureau estimates that the global population exceeded the threshold on 26 September, though the agency said to take this precise date with a grain of salt.

The United Nations estimated the number was passed 10 months earlier, having declared 22 November 2022, the “Day of 8 Billion”, the Census Bureau pointed out in a statement.

The discrepancy is due to countries counting people differently — or not at all. Many lack systems to record births and deaths. Some of the most populous countries, such as India and Nigeria, haven’t conducted censuses in over a decade, according to the bureau.

While world population growth remains brisk, growing from 6 billion to 8 billion since the turn of the millennium, the rate has slowed since doubling between 1960 and 2000.