How do you know the number of verified users that contribute to the IMDb ratings?

@rouge09 This is shown under the rating at the top of the title page.  For example on https://www.imdb.com/title/tt15398776/

there are over 546,000 votes.  You can also click the rating to see a more detailed breakdown and count, as in https://www.imdb.com/title/tt15398776/ratings/

Hope this helps.