count number of cells in Column C that have a lesser or equal value to the adjacent cell

=sum(if(C1:C100>D1:D100),1,0))-sum(if(c1:c100=0,1,0)*if(D1:D100=0,1,0))

as an array formula (confirm with ctrl+shift+enter)

Hi Yudlugar, Unfortunately that reported a function error (highlighting the D100 in the first range) However the array that Nathansav posted at 10.00a.m works fine.

Thank you for your help.