Sociological poll's results are clustered

Occasionally I watch some TV news programs that do polling on various political and social issues. First of all - the fact of existence of such polls is curious by itself, since it depicts how many simple minded peoples there is out there happily paying for the phone calls to poll numbers just to express their opinion. In my view all those polls are nothing more that side revenue generation options for TV/phone corps and specifically designed for it. Anyway I've noted an interesting fact - those results have some clustering patterns - both in time and quantitative space and let me explain what I mean. Quantitatively - results are always clustered around the following ratios: 98:2 90:10 2/3: 1/2 1/2: 1/2 I didn't done a massive statistic on it, but it's my observation. Isn't that curious? Now regarding "time clustering" - if poll results would be very biased, i.e. huge majority in favor of a certain option (like 98:2 or 90:10) - then usually during the very first seconds (something like 30 - 40 sec's) of the poll - the minority option would be the leading one! It's seems like people supporting an option which is really not favorable in view of the majority are reacting much more actively than the average citizen.