Returns the value of the distribution function for age at death \begin{equation} \deathdist(x)=1-\sfrac(x). \end{equation} If MortHandle is a multiple decrement mortality this function returns the value of the distribution function for dying from Cause on or after Age \begin{equation} \deathdist_\cause(x)=1-\frac{\sfrac_\cause(x)}{\sfrac_\cause(0)}. \end{equation} Cause is a comma-separated list of cause codes possibly prefixed by '~' to denote the complement.