Esperanto Speakers: No Significant Change in Numbers

I wanted to know whether the number of Esperanto speakers is growing or shrinking and found a Linguistic StackExchange post by Alexander Galkin helpful. In a part of his answer, he wrote:

Another metric is the number of people who participate in Universala Kongreso — the annual world conference of Esperanto-speakers. I don’t have a diagram for this statistic, but you can see the numbers here. The fluctuations here are much bigger and there is no clear trend — either increasing or decreasing — seen there.