How the hell has this show droped to a 7.5

It went from over a 9 to 7.5 in a matter of months, wtf is that?

Nature is easily the best natural world documentary series out there, I even put it over the Attenborough stuff, given the depths of its subject matter those who make these documentaries go to. The structure of each episode is absolutely bleeding quality, I know its only out of like 200 reviews or so but who the hell is raging on nature lol to knock it down to a 7.5 so fast?