Hongkong: „The estimated burden of tutoring costs per child reached between 20.3 % and 30.5 % for households with estimated incomes between HK$ 4,000 and HK $5,999.“
Univ.-Prof. Dr. Mark Bray, „Benefits and Tensions of Shadow Education“. In: „Journal of International and Comparative Education“ (2013), Vol. 2, Issue 1, S. 22