The adoption rate is the rate of adoption over time.

One could try to make an argument that "adoption rate" should mean change in adoption over time, but the meaning as used in this article is unambiguously not that. It's just percentages, not time derivatives, as clearly shown by the vertical axis labels.

	▲	brianshaler 4 hours ago \| parent [-]
		There's another axis on the charts.

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2 hours ago | parent | prev | next [-]

[deleted]

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pclmulqdq 5 hours ago | parent | prev [-]

Normally, the adoption rate of something is the percentage ratio of adopters to non-adopters.