Tell me your gain I'ld tell you your value

There are several ways to know how is your income payement.
One idea is to read studies, articles, surveys and anything published around the subject but it's still about national or continental medium salaries confusing big cities and countrysides.
First of all the close network: work-colleagues, friends, family. Then the ''social network'' meetings inter-professional relationships and people who revolve on our business.

Today I've discovered a new one.
I do have had phone calls from students looking for internship (sorry but my status and my activity are not allowing me to work with collaborators), the commercial sollicitations, here was a poll about ''purchasing power''. And it's only for people paying more than 3,000 euro in income taxe.




So I wondered how much you have to gain as you are able to give your opinion about purchasing powwer (one year before the presidential campaign...). Fastly, I would say that to pay 3,000 euro in income taxe this year you need to have gained more than 28,000 in net incomes (single or in couple with a similar level of income, childless without taxe-fees).
As the french legal minimal salary is around 16,000 euro a year, you could think that people in a precarious professional situation does not be concerned with purchasing power...

Then I have a other question: why me?
I mean, how are selected the phone numbers to respond to this study? I hope it's not according to the tax declarations we returned recently! Perhaps a random directory (this is the basic for an opinion poll, isn't it?).
But I have a doubt thinking that the incoma to pay the expected tax level (so here are the famous ''middle classes''?) is close to the maximal benefits for an ''auto-entrepreneur'' (I occasionally work with this status for a year)... in this case we could think on a targeted poll to play on statistics with a favorable public that believe to gain a little more money with this new ''lighted'' professional tax system... nooooo, it could not be....