Get Historical Trend


We are developing a application in which we need the data total followers betweet two given dates(historical data). But what i get from API is the real time data. But not the historical data.

If i understand correctly we can’t get the data using Twitter API(Concluding based on past discussion threads). Correct me if i am wrong.

My question - There are manay commericial websites like are able to get the data on fly(if i add new twitter account then i can able to show the historical trend).

I want to know how they are able to do it? We want to use the approach. Can you please let me know what are the possibilities that can think of here.
Is there anything with Twitter API (Commericial) that i can pay money and they can provide the access to historical data?

All i need how other commerisal websites are able to get and i need to evaluate those options and choose the best one.

Please let me know at the earlist.

Thank You,