I've also been getting these calls several times a day for a couple of weeks (Albany, CA).
A little googling suggests that "YPR" stands for "Yellow Pages Research", which seems to fit with some other people's experiences.
I just called the number myself (248-630-2829) and received a recording asking if I wanted to be removed from the call list. To do this I had to key in my number. I then got a message that said my number will be removed within two business days. We'll see.
Ordinarily I'd be wary of entering my number, but I figure they already have it anyway so....
After several calls (including Sunday) I answered and the caller said she was calling from Yellow Pages Research. I asked her not to call again -- we'll see.
Same. Calls daily sometimes more than once. We have answered before but now we just ignore it. Area code 248 is Oakland County, Michigan (near Detroit).