Well, I mean from electrocution specifically. 100-200mA through your heart is probably going to be fatal, and the low resistance required for that to happen with a simple 9V battery source has at least once been achieved by inserting multimeter probes in the thumbs such that the current passed via the blood stream through the heart, causing fibrillation.

Interestingly, there exists a sort of upper threshold where the amperage is less likely to be fatal due to severe cramps preventing fibrillation IIRC.

0.018 is way above the threshold of sensation, well into the territory of very painful shocks (18 times the threshold of sensation at ~1mA). Of course this will usually be local with a 9V battery, but with some deliberation you can pass the current through your heart via the blood stream, where the resistance is sometimes much lower which can get you very close to what'll likely be fatal.

Edit: the above holds true for AC but not necessarily for DC from a battery, where the thresholds are typically higher. But the heart is very sensitive and fibrillation occurs at very low currents passing directly through it.