What was San Fransisco's growth in population due to the hippies?

I need to do an informative speech for my speech cl. My teacher wouldn't let me choose any of the topics I wanted to do because they were either unethical (like how to get out of a speeding ticked), or she said it wouldn't interest the cl (like the most loosing team in sports history). So after about 7 other topics that everyone else in my cl thought as interesting that she refused to believe the cl would think are interesting, she decided to choose a topic that she thought the whole cl would find interesting. So she decided that why was san fransisco the Capitol of the hippie movement better than all of my ideas. So If you have any websites or information over that topic it would be help full. And I need to know about the population growth in San Fransisco because during the hippie movement. Some websites on that or some stats would be help full. Thanks!!! And if you give me information, it would be very help full if you listed your sources.