How do I find microphone output voltage?

Hello,

How can I calculate the output level of a microphone,
I assume it is found from the Sensitivity , but how?
For example, I want to know what voltage I will
get if the SPL is 60dBA (on the sound level meter)

For example, I find in the data*** Sensitivity = -40dB
Assuming this is actually dBV, then it should be 10mV
(1Volt/100), but at what SPL is that taken?

Thank in advance
Mic.

.