“To anyone reading, have you ever been part of a national poll?”
Since most polls only have about 1,000 adults, your chances of being selected for any given poll are 1 in 250,000. Thus, even if there are 100 polls a year, your chances of being selected are still only 1 in 2500.
Actually, your chances of being selected for any given poll are 1 in 313,232.
https://www.cia.gov/library/publications/the-world-factbook/geos/us.html