A 2012 study reported that almost 6.5 million tonnes per year were consumed globally while a later study estimated that global demand in 2015 was between 7.3 million and 9 million tonnes.
ɐ tˈuː θˈaʊzənd twˈɛlv stˈʌdi ɹᵻpˈoːɹɾᵻd ðæt ˈɔːlmoʊst sˈɪks.fˈaɪv mˈɪliən tˈʌnz pɜː jˈɪɹ wɜː kənsˈuːmd ɡlˈoʊbəli wˌaɪl ɐ lˈeɪɾɚ stˈʌdi ˈɛstᵻmˌeɪɾᵻd ðæt ɡlˈoʊbəl dᵻmˈænd ɪn tˈuː θˈaʊzənd fˈɪftiːn wʌz bᵻtwˌiːn sˈɛvən.θɹˈiː mˈɪliən ænd nˈaɪn mˈɪliən tˈʌnz.