Correlations of VHE luminosity between 1 TeV and 10 TeV of L_VHE (top) and (L_VHE∕L_radio) (bottom) with source age, where L_radio is the luminosity at 1 GHz. Points: detected shell-type SNRs in the VHE regime. Arrows: upper limits. Red: shell-type SNRs. Blue: thermal composite SNRs. Values for Kepler’s SNR, G1.9+0.3 and G330.2+1.0 from Aharonian et al. (2008a) and Abramowski et al. (2014b). Grey lines and uncertainty bands: Best-fit correlations taking only the detected SNRs into account. Red lines and uncertainty bands: Best-fit correlations when including also those upper limits into the fit where SNRs fall into the age interval defined by the sample of VHE-detections (<5.1 kyr, upper age limit of RX J0852.0 −4622).