This

It's random.
Statistically it's possible (although highly improbable) to get none for a whole month.
Collect accurate data for at least a year, then ask the same question.

Pretty sure if you search through threads i've made you'll find me complaining about this too but right now im doing alright with them.

Its all luck of the draw, some days i'll get 6, some i'll get 20.

Its fully random.

when im at max plus my Base drop once a day i generally get 8 Resc Prisoners, but on avg 100k is when i pull and i get 3-4 resc. ive jumped up like 10k in the past 4 months in awesome.

On average it is 1 of everything every 95,750 arti points claimed.
I repeat, for every 95,750 artifact points you claim, you will get 1 of each artifact on average.
Unless of course you manage to claim strictly under 20,000 points to avoid the mass storage pod, if you can manage this then ever 75,750 arti points claimed will get you 1 of everything else.

If your artifact/hour is kinda small then this average isn't abundantly clear since you are taking such small sample sizes.

Now if you were to say open 50 caches with an artifact/hr over 100k then you will be able to see for yourself that the math is quite right.

With my art pull & Legion pull combined, it's over 80k, and I just
let it build up till the pull.
I've received 17 prisoners once and usually 1 a day normally.

This makes 100% sense and is mathematically sound if you assume there is equal odds of each artifact. I've actually tracked the data for myself. I started out at about half as many prisoners as I should be getting. Thst was stable until I made a post about it. Since then, prisoner drop rate has been going up slowly and is now about right. Probably coincidence that it went up as soon as I posted about it, but I like to think that I uncovered a conspiracy that has since been corrected.

Thanks for the replies guys!

I normally clear my arti trade between 140-200k, and usually would pop 1-5 RP. But lately this entire week i been pulling 1 RP every load.

Except yesterday... after this post, I got 7x RP from 180k lol!! That answered my question

Well, as your IGN IS Stinker, what did you expect?

im right there with ya mine have dropped off as well but cant really complain had a good solid month of getting between 15 - 20 a day, im down to about half that which is still nice, so will just wait for the sun to shine once more