Although there are no set numbers provided to pass the PE Exam, it is believed, according to research that you will need to correctly answer approximately 70% of the questions. That's about 56 right answers out of 80. This is just an approximation, based on opinions given by multiple people
According to datausa.io, the percentage of civil engineers compare to all other majors is 1.72%. This number is also decreasing, which means we see fewer civil engineers. This means there will be a higher demand for this type of engineering.
As far as becoming a professional engineer, as the above post stated, one needs to obtain a 70% of the PE exam to become a professional engineer.