What percentage of Iran practices Zoroastrianism as opposed to the percentage of Musl

I've recently been corresponding with an Iranian that practices Zoroastrianism rather than Islam. After research I found that it was a very strong religion in Persia. I'm wondering what percentage of Iranians still practice this way of life?

90% of people believing in zoroastrian but they are muslims by name and they can not convert to other religion because of islam.a muslim can not be converted to other religions and if some one be brave enough to do so must be executed.this is islam rule.they not even free to chose their religion ,because your father was muslim by force you must be muslim as well,that's it.can you tell me what's the meaning ,when 60 million people in iran celebrating the last wednesday of the year and they making fire every where or why their new year is not same as muslims?! Why 60 -70 million persian celebrating their new year in zoroastrian way.
That means something ,isn't it?

According to the link below there's about 45,000 practicing Zoroastrians in Iran:

http://news.bbc.co.uk/1/shared/spl/hi/picture_gallery/05/middle_east_zoroastrians_in_iran/html/1.stm

But there are probably more who practice the religion in private. Zoroastrianism Prue-dates Islam in Iran by at least 2500 years (modern scholars place 1700 BC as the date when Zoroaster lived).