Those who you Respondent, how often do you get a hit?

I signed up for Respondent a few weeks ago. Luckily, I got contacted by someone right away, and it paid well! (Luckily my first contact was quick otherwise I'd probably not take it seriously).

I'm hoping to get another one, but no matter how qualified I am, they're not contacting me.

How often do you guys get surveys invites?