perl -le '$Da=406700; $Dp=356400; $Dm=361918; $pct = ($Da - $Dm) / ($Da - $Dp); print $pct'

##</code><code>##

perl -Mbignum -le '$Da=406700; $Dp=356400; $Dm=361918; $pct = ($Da - $Dm) / ($Da - $Dp); print $pct'

##</code><code>##

perl -Mbignum -MAstro::Units -le '$Da=406700; $Dp=356400; $Dm=361918; $pct = ($Da - $Dm) / ($Da - $Dp); print $pct'

##</code><code>##

perl -MAstro::Units -le '$Da=406700; $Dp=356400; $Dm=361918; $pct = ($Da - $Dm) / ($Da - $Dp); print $pct'