Distributions of central ring parameters (from left to right): Radius, r_ring, relative radius, r_ring/r₂₅, molecular gas mass, $M_{\mathrm{mol}}^{\mathrm{ring}}$, ring molecular gas mass fraction, $M_{\mathrm{mol}}^{\mathrm{ring}}/M_{\mathrm{mol}}^{\mathrm{gal}}$, star formation rate, SFR_ring, ring SFR fraction, SFR_ring/SFR_gal, depletion time, $M_{\mathrm{mol}}^{\mathrm{ring}}/{\mathrm{SFR}}_{\mathrm{ring}}$, and relative depletion time, $t_{\mathrm{dep}}^{\mathrm{ring}}/t_{\mathrm{dep}}^{\mathrm{gal}}$. The distributions are shown for the whole sample on the left and for spirals only on the right, thereby leading to the different numbers N = {…} considered for the distributions. The violins show a smoothed distribution, the boxes contain the 25th to 75th percentile of the distributions, the black whiskers span out to 1.5 times the interquartile range, and the circles mark outliers beyond this range. The median is shown by the black horizontal line. The respective values for the MW CMZ are plotted as black diamonds along with their error bars in red.