[Extension()] public static Nullable<double> AnnualInterestPercent( Debt debt, Nullable<AnnualInterest> annualInterest )
Parameters
- debt
 - The estimated cost-to-fix a set of issues, it can be negative in case of debt-diff value.
 - annualInterest
 - The nullable cost-to-not-fix per year a set of issue, it can be negative in case of annual-interest-diff value.
 
