Creating measure based on 2 statements

[# Alerts] = COUNTROWS( T ) // T being your table

[Kidnapping Rate] =
DIVIDE(
    CALCULATE(
        [# Alerts],
        KEEPFILTERS(
            // Names of columns should be
            // as short as possible but
            // still meaningful.
            T[Incidents with Crew Kidnapped] = "YES"
        )
    ),
    [# Alerts]
)

I warn you against having one-table models and not following the star schema. Watch this: https://community.powerbi.com/t5/DAX-Commands-and-Tips/Why-one-table-models-will-produce-WRONG-NUMBERS/td-p/1904161