Reports by the Congressional Research Service from 2008 discuss emerging policy issues regarding carbon dioxide pipelines for carbon sequestration, network needs and cost uncertainties regarding pipelines for carbon dioxide control, and jurisdictional issues in regulating carbon dioxide sequestration pipelines.
Total numbers of speakers is high: over 40 million Farsi speakers (about 60% of Iran's population); over 14 million Dari Persian speakers in Afghanistan (50% of the population according to CIA World FactBook & Britannica); and about 2 million Dari Persian speakers in Pakistan.
Ethnologue breaks up Kurdish into three large groups: Central Kurdish (Kurdi, Sorani) is spoken by 3.5 million people in Iraq and by 3.2 million in Iran. It is also spoken in Armenia, Azerbaijan, Georgia, Iran, Iraq, Lebanon, Syria, and Turkmenistan (Ethnologue). The total population of speakers of Central Kurdish is estimated at 6.8 million speakers (Ethnologue). There are 10 varieties of Central Kurdish.