Indian schools of philosophy are traditionally divided into two categories, Astika and Nastika. Astika schools accept the authority of the Vedas as divinely revealed truth (shruti), whereas Nastika schools, like Buddhism, Jainism, and Charvaka, reject the authority of the Vedas. Generally members of Astika schools are the ones that are called Hindu, whereas the Nastika schools fall into the broader category of Dharmic faiths. In any case, here are the traditional Astika schools of philosophy:
But it seems to me that one school is vastly more popular than the others: the Vedanta school, which derives its tenets from the philosophical teachings of the Upanishads, as expounded in Vyasa's Brahma Sutras. Here is Wikipedia's chart of the various Vedanta philosophies:
From what I can tell, almost every popular sect of Hinduism subscribes to one of these Vedanta philosophies. Smarthas, for instance, believe in Adi Shankarachatya's philosophy of Advaita Vedanta, according to which Jivatma (the individual soul) and Paramatma (divine soul or supersoul) are identical. Sri Vaishnavas believe in Ramanujacharya's philosophy of Visistadvaita Vedanta, according to which Jivatmas are distinct parts of Parmatma but Paramatma extends beyond them. And Gaudiya Vaishnavas believe in Chaitanya Mahaprabhu's Vedantic philosophy of Achintya Bheda Abheda, according to which there is a simultaneous unity and difference between Jivatma and Paramatma that is inconceivable.
So my question is, what is the percentage of Hindus who belong to a sect which subscribes to the Vedanta school of philosophy? Note that when I say "Hindu" I don't mean Buddhists and the like, I just mean people belonging to the Astika schools. I'm wondering how many Hindus belong to the Vedanta school, compared to how many Hindus belong to the other Astika schools like Purva Mimamsa.
My guess is that the percentage is significantly greater than 95%, but have there been any statistics collected on this?