The Rohingya people have consistently faced human rights abuses by the Burmese regime that has refused to acknowledge them as Burmese citizens (despite some of them having lived in Burma for over three generations)—the Rohingya have been denied Burmese citizenship since the enactment of a 1982 citizenship law. The law created three categories of citizenship: citizenship, associate citizenship, and naturalised citizenship. Citizenship is given to those who belong to one of the national races such as Kachin, Kayah (Karenni), Karen, Chin, Burman, Mon, Rakhine, Shan, Kaman, or Zerbadee. Associate citizenship is given to those who cannot prove their ancestors settled in Myanmar before 1823, but can prove they have one grandparent, or pre-1823 ancestor, who was a citizen of another country, as well as people who applied for citizenship in 1948 and qualified then by those laws. Naturalized citizenship is only given to those who have at least one parent with one of these types of Burmese citizenship or can provide "conclusive evidence" that their parents entered and resided in Burma prior to independence in 1948. The Burmese regime has attempted to forcibly expel Rohingya and bring in non-Rohingyas to replace them—this policy has resulted in the expulsion of approximately half of the 800,000 Rohingya from Burma, while the Rohingya people have been described as "among the world's least wanted" and "one of the world's most persecuted minorities." But the origin of ‘most persecuted minority’ statement is unclear.
How many of the  Rohingya people have new changes in citizenship caused to become refugees ? 
expulsion of approximately half of the 800,000 Rohingya from Burma,