Median fractional polarisation over total intensity. Data from the literature compared to our Apertif GN, SVC data and the combination of both in plot (a), the grey error bars to the full Apertif sample represent the sample variance, the area in which the individual bootstrap samples are located is visualised in grey. Plot (b) presents the individual GN and SVC fields as lines. Plot (c) shows the effect of bandwidth and beam depolarisation on selected data sets from the GN and SVC data. The dotted line in each plot gives our detection limit of PI ≥ 90 μJy.