Hello, NelBo; good to meet you!

When you view your stats, you are shown a graph of 30 vertical, green bars, which show your views, reads, and fans. As each day passes, you will gain a day (a new bar) at the end and lose a bar at the beginning.

You won't notice this during your first 30 days of activity on Medium because you won't have been active for a full month yet, so your stat caunt will generally increase each day. Once you reach Day 31, however, Day 1 scrolls off your bar graph, which can cause your stat numbers to fluctuate. They will continue fluctuating every day after that. Some days you'll have more; some days you'll have fewer views, reads and fans.