What percent of people have left a website after forgetting their password rather than using the password recovery option?
Study: Consumer Perceptions of Online Registration and Social Login
Date: October 2011
How often have you gone to a website, forgotten your username or password and decided to leave the website instead of going through the process of re-setting your password or answering security questions? (n=616)
90% left the website
The answer provided in the paper doesn't seem to match the question since it does not provide information on how often this happens. The authors may be combining any answer that was not "Never" to arrive at the 90% figure.