Where do you fetch the statistics from ? Iran has a semi secular urban elite but the rural masses and slum dwellers are quranimals. If they are going to rise against the Ayatollah regime it's because of socio-economic failure of their regime.
Secular parties there make up a large amount of the parliament, a third at least. Also keep in mind Iran is undergoing lots of urbanization and the vast majority of ppl in those urban areas don't give two flying ****'s about Islam, espeicially the young ones. The 80% statistic comes from the Iranians themselves, 80% of Iranians under 25 don't pray, go to mosque, and have friends from the opposite gender. Also keep in mind that Ahmadinejad isn't favored by the Islamist hard-liners over there and he has been making his platform more secular to appeal to the younger vote