Summary statistics for stage-II (Heymans et al. 2012; Jee et al. 2016), stage-III (this work; Sevilla-Noarbe et al. 2021; Hikage et al. 2018; Guinot et al. 2022), and stage-IV (Euclid Collaboration 2022; The LSST Dark Energy Science Collaboration 2018; Gong et al. 2019; Eifler et al. 2021) cosmological imaging surveys, comparing the survey area and effective number density of sources for weak lensing analyses (square markers). The red curves show the total effective number of sources, which principally determines the cosmological constraining power. The colour bars indicate each survey’s wavelength coverage, which principally determines the photometric redshift quality of a survey. The size of the circular point within each survey’s square marker shows the typical seeing in the lensing band, which principally determines the accuracy of shape measurements. The statistics presented for future surveys are forecasts, as indicated in pink. The final DES-Y6 data release will increase in depth, relative to the DES-Y3 statistics shown, raising the final effective number density of sources.