The chart below shows how Shall Issue laws for the licensed carrying of firearms for self-defense have become the American norm.
As of 1986, slightly less than 10% of the U.S. population lived in states where there were objective and fair procedures for the issuance of concealed handgun carry permits. About a third of the population lived in states where there was not even a process to apply for a permit. The majority of the population lived in states where issuance in permits was highly discretionary, and many issuing authorities refused to issue to ordinary law-abiding citizens.
Read the article: The Volokh Conspiracy