Comparison of velocities and line widths of ammonia maser lines to the intrinsic line widths of ammonia (J, K) = (1,1) thermal emission. The number of data points is substantially larger than the number of newly detected sources due to the occasional presence of more than one maser line in a given source and more than one velocity component in a specific maser line. δV = V_LSR(maser) − V_LSR(NH₃(1,1)) is the deviation from velocities of the NH₃ maser lines to those of NH₃ (1,1) thermal emission. δWidth = ∆V_1/2 (NH₃ (1,1))-∆V_1/2(maser) refers to the difference between the line widths of ammonia maser lines and the intrinsic line widths of an individual NH₃ hyperfine structure component. The dashed green lines indicate positions with zero deviation. The metastable NH₃ transitions are marked in blue. Among the non-metastable NH₃ lines, ortho-NH₃ is presented in black and para-NH₃ is given in red.