Isn't this showing the percentage of bot traffic from the Yandex IP range?

If so, it isn't particularly surprising that the line would go down.

EDIT: yes, it is. Looking at the same graph for all of Russia, and there's no discernible pattern:

same for the 48h view:

USA accounts for 44% bot traffic worldwide. Russia 0.9%. Russia derangement syndrome on HN as usual.

	▲	CaptWorld 10 minutes ago \| parent \| next [-]
		The only valid derangement syndrome is Russian derangement syndrome and I'm proud to have it
	▲	cowlevel an hour ago \| parent \| prev \| next [-]
		This is true. Almost all of my website's bot traffic is from USA.
	▲	876433790 12 minutes ago \| parent \| prev [-]
		[dead]