Why don't you create a poll for this question? for type of this question, you might get more answers with Yes or No only.
The best way to know how many percentages of websites are using DSL out there is using Google. try to find with a keyword and see Top 100 results. There are how many sites are using certificates and you will got the answers for your questions.
Hi. Today every site need SSL. If your site dont have SSL, Chrome writes in the address bar that the connection is not secure, Firefox warns users that it is better don't enter authorization data. Which user will like it? Btw, nowadays, with free SSL like Let's encrypt, installing a certificate does not require any costs and takes several minutes.
My questions was "How many of you use SSL certificate for your website?". Do you read those before posting? No one asked you to calculate how many websites ranked in Google use SSL certificates and the conclusion that if 30 of the top ranked websites use SSL, this means that "100% of sites is using https" is not true. There is no proportion here and even if it was, it is not the way to calculate it. still this conversation we are having has nothing to do that you did not answer the question and simply changed the topic of the thread.
I'd like to believe that every new user on the internet knows - SSL is a great addition to the website, which you can get for a free nowadays. Most of the hosting panels offer easy installation. cPanel even installs the AutoSLL automatically, once you add the domain. If someone doesn't use SSL by now, it's most likely due to lack of knowledge about the SSL.
To put it simply, if you want your websites be felt secured to visit, it is required for your website to have an SSL. It not only increases reliability of your site to the visitors, but also helps in secure transfer of data in between the server and the visitor's browser. It's totally upto you to decide whether or not to go with the SSL certificate in your site. What's more, SSL is highly preferred by the entreprise however, it is less valued by small and medium sized business.