Calculating laser fluence -- so confused

Hi,

I'm now endeavoring to calculate laser fluence using some laser parameters.

The required parameters to solve the fluence are given as:

Spot size: 10mm diameter
Pulse duration: 200ms
Repetition rate: 2-3 (Hz)
Laser Power: 200mW (when measured by a power meter)
Wavelength: 660nm

I have several different results ranging from 0.18J/cm^2 to 0.7J/cm^2

I'm always so confused with fluence calculation.

Anybody please can help me clearly?