I also received a call from this number on my cell phone.  Busy tone when I called back.  Second phone call in two days from the number.

call came in 6/13 at 853pm

Received a call from 573-775-4536 lady stated they were taking a poll for corn stats.

I seem to be receiving telephone calls from this number on my cell phone which shows up Private and my office phone which shows up as MISSOURI. There's never a message left.  Curiousity is going to force me to call back then I'll report back to this site.  However, by looking at the comment prior to this, it seems there's been no answer in the past attempt to call it back.

unknown caller: I called back ring no answer