Figure 2.2 shows the funding source of R&D spent for selected countries across the different income groups. However, the eligible expenditures to be counted as ODA has evolved since with decisions to include administrative costs, imputed student costs and refugee costs during the 1970s and 1980s. ( Hynes and Scott, 2013[8]). Similarly, the statistical reporting of ODA has evolved through the decades, moving from aggregates to activity-based reporting through the Creditor Reporting System.