On 22 Jul 2018, "Mayayana" wrote in
alt.windows7.general:

I also suspect that such a service would only make
a small dent in the problem.

I keep a log of all junk phone calls, and I get a lot of them. I'd say
that Nomorobo catches about 85% of them. It used to do better but the
robocallers have gotten better at exploiting weaknesses in the system.

85% is still a big relief.