I'll Bet You An Upvote You Won't Guess How Many F's Are In This Sentence

Here is the sentence: FINISHED FILES ARE THE RESULT OF YEARS OF SCIENTIFIC STUDY COMBINED WITH THE EXPERIENCE OF YEARS

You can count as many times as you'd like before scrolling down, best of luck.

If you can guess the correct number of F's in this sentence, I don't want your upvote.
I'm gonna tell you what the number is and prove to you that it is correct down below.
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The correct number is 6.

1. Finished
2. Files
3. oF
4. oF
5. ScientiFic
6. oF

We're not 100% sure why humans don't get this right almost ever. Our best answer is that perception is subjective, and we all perceive reality through our own subjective lenses of the culture and religion we we raised in, along with the values we've adopted and our beliefs about the world.