The results in Table 3, for average year-specific and window-specific efficiency scores suggest that there is considerable room for improvement. More specifically, the lowest and highest year-specific mean efficiency scores are [85.5%-91.4%], [85.5%-91.6%], [85.9%-92.6%] and [88.2%-93.9%] for groups A, B, C and D respectively. The detailed results (not presented here) showed that the hospitals that exhibit the lowest efficiency scores for each group are A1 (49.8%, year 2013, window 2012–13), B14 (57.7%, 2010, window 2009–10), C2 (55.2%, 2009, 2009–10) and D9 (57.6%, 2010, window 2010–11). In the same table, the number of fully VRS efficient hospitals is also presented. Thus, year 2011 within window 2010–11 accommodates the highest number of fully efficient units for groups B, C and D. More precisely there are 14, 16 and 15 fully efficient units accounting for 42.4%, 53.3% and 65.2% of the total number of units for groups B, C and D respectively. In group A, the highest number (11) of fully efficient units appears in year 2013 within windows 2012–13. In addition, the VRS efficiency scores for groups A and B show the highest and lowest spread respectively, as evidenced by their corresponding standard deviations (and minimum values not presented in the table). As it can also be seen from the Table 3, the window-specific efficiency scores appear to have an increasing trend until window 2011–12 after which they are reversed and start to deteriorate.