How many adherents does shi'ite have?

Answer 1

It depends on the way the question is read.

How many people believe that Shiites exist? -- Most of the world's population acknowledge that Shiites exist, because there is irrefutable evidence that there are individuals who follow Shiite Islam.

How many Shiite Muslims are there? -- The Pew Report and other similar groups hold that there are between 154 million and 200 million Shiite Muslims in the world today. Other organizations run by Shiites like Liveform have estimated that there are over 400 million Shiites. Please see the Related Link below.

Answer 2

Muslims in world are near 80% sunni and near 20% shia. researchers have counted up to 260 sect for Islam that they all belong to categories Sunni and shia. the main category of Shia is 12 Imami shia and other sects of shia are nearly extincted.

there is at least 300,000,000 shia Muslims in world, but there is no clear stat. shias always have been controlled and killed during history and so usually they hide their beliefs. all 12 Imams of shia have been killed or spent their life in prison by Omayyads and Abbasids.