i think at least 80 per cent of people will be using bitcoins by 2020 because it will surely be much more popular then
I think you are super optimistic about bitcoin and such events may not happen easily even in 2025 or 2030.
Of course it requires a lot of time before we can see a massive adoption with bitcoins, government can easily make any laws the prevent the usage of bitcoins if they feel treated that their currency will be overpower by bitcoins so it is still very risky for the people to use and trust their hard earned money with bitcoins.