Pained Soul - % spawn rate is .002 not .02

[Koopmd]

I was told that Pained Soul spawn timer is 2%.
2% should be 2 every 100 right? And I realize it can skew but it is spawning 1 in 360 times (once every 40 hours) ... that is 0.0027 ... or .2% not 2%. Is this correct?

Thank You!