Didn't think it would get that complicated. I just did select the reviews myself, and came up with the following:
Week 1: 10th Sept - 17th Sept: 41 positive out of 132 reviews
Week 2: 17th Sept - 24th Sept: 39 % positive out 105 reviews
Week 3: 24th Sept - 1st Oct: 48 % postive out of 174 reviews
Week 4: 1st Oct - 8th Oct: 42 positive out of of 276 reviews
Week 5: 8th Oct - 15th Oct: 47 % positive out of 175 reviews.
Week 6: 15th Oct - 22nd Oct: 51 % positive out of 150 reviews.
I selected all languages and Steam buyers only, so we all seem to be getting slightly different figures after all.
Anyway, from my point of view, it’s pretty obvious that Civ7's reviews are more or less stuck in the 40–50% positive range. Last week, Civ 7 was at 51% positive. If you think that’s the beginning of a great comeback, that’s up to you. For me, it just looks like normal statistical noise, similar to what happened in Week 3, when the positives jumped from 39% to 48%. In Week 4, it went down to 42% positive again, which, by the way, had by far the most reviews during this period.