Jet fraction statistics for the universal structured jet model assuming the GW170817/GRB170817A structure. Top row: Median jet fraction f_j versus the predicted local BNS merger rate density R_BNS(0) (left) and total integrated rate Λ (right). Bottom row: Quantile of the posterior distribution of f_j at f_j = 1 as a function of local BNS rate density (left) and total integrated rate Λ (right). Symbols are coloured according to the α_CE parameter, and each symbol denotes a different population. The shaded vertical region indicates the 90% credible interval for the BNS merger rate from GWTC-4 (The LIGO Scientific Collaboration 2025). The cited fractions from the works of Ronchini et al. (2022) and Loffredo et al. (2025) are given as R22 and L25 for comparison.