From anecdotal evidence: I got to know this cute and smart girl, but she was in a long term relationship at the time. At some point I learned through a common friend that she broke up a month and a half ago. I asked her out, and she told me she has been dating this other guy for a month. So, basically, she was single for two weeks.
With my friends, we call "high quality" girls, girls that are good looking, smart and nice, have a job/passion in their lifes, or have something going on for them. They are very rare. Actually, extremely rare around here. You might meet good looking girls, but that have nothing else going on for them in their lives, you might meet smart girls, but that are just not attractive to you. The combination of smart + good looking is a real killer, and often is ruined by "bitchiness", but that is very subjective.
It seems that women become "nicer" and easier to talk to as they get older. Especially in their 30s and so, when they clock is ticking. But in their '20s', it is tough to find a girl like this Carol.
Maybe Carol needs to move to SF. She will have the pick of the litter.