**Table 9:** Intensity ratios between the high density tracers.
Galaxy	$\frac{\rm HCN}{\rm HNC}$ 1-0	$\frac{\rm HCN}{\rm HNC}$ 3-2	$\frac{\rm CN}{\rm HNC}$ 1-0	$\frac{\rm CN~2--1}{\rm HNC~3-2}$	$\frac{\rm CN}{\rm HCN}$ 1-0	$\frac{\rm CN~2--1}{\rm HCN~3--2}$
NGC 3079	2.15 $\pm$ 0.67	1.60 $\pm$ 0.75	0.64 $\pm$ 0.20	1.25 $\pm$ 0.58	0.30 $\pm$ 0.09	0.78 $\pm$ 0.25
NGC 1068	2.01 $\pm$ 0.65	6.48 $\pm$ 1.95	1.98 $\pm$ 0.58	2.58 $\pm$ 0.78	0.98 $\pm$ 0.29	0.40 $\pm$ 0.29
NGC 2623	1.4^a	$\la$ 0.26	$\la$ 0.77^a	-	$\la$ 0.5^a	-
NGC 1365	1.35 $\pm$ 0.37	-	0.87 $\pm$ 0.25	-	0.64 $\pm$ 0.17	0.67 $\pm$ 0.19
NGC 7469^b	1.50 $\pm$ 0.57	-	0.85 $\pm$ 0.28	-	0.57 $\pm$ 0.21	-

^a: Ratios reported by Aalto et al. (2002).
^b: New ratios computed using the HCN 1-0 source size estimated from Davies et al. (2004).