fiscal investor confidence divide by 0

[cwp-bot]

error spam regarding a div-by-0 error in the fiscal_investor_confidence_calculation.

13:24:13.053: [2023-08-02 13:24:13.100] [Clausewitz Error] [error] [jomini_scriptvalue.cpp:252] Div/0 near file: common/scripted_effects; fiscal_investor_confidence_calculation line: 3

[DZappala]

13:26:10.170: [2023-08-02 13:26:10.538] [Clausewitz Error] [error] [jomini_scriptvalue.cpp:252] Div/0 near file: common/scripted_effects; onaction_imf_contribution_calculation line: 15