Fig. 1

Schematic overview of different lookback approaches. 1; 4 years fixed LP (2012–2018), 2; 6 years fixed LP (2014–2018), 3; 8 years fixed LP (2016–2018); 4, All available data (2012–2018 allowing minimum 4 years of LP resulting in varying LPs). In case examples A and B, the red arrows represent the retrospective lookback period and grey arrows represent deletion of historical data when applying a fixed LP