Here is an example that shows that @jthi column does work.  I believe that you have an issue with your data.  
New Table( "Untitled 12",
	Add Rows( 4 ),
	New Column( "N(1.6)",
		Numeric,
		"Continuous",
		Format( "Best", 12 ),
		Set Values( [445, 446, 0, 0] )
	),
	New Column( "N(1.5)",
		Numeric,
		"Continuous",
		Format( "Best", 12 ),
		Set Values( [0, 0, 441, 446] )
	),
	New Column( "MAXRESULT",
		Numeric,
		"Continuous",
		Format( "Best", 12 ),
		Set Values( [1.6, 1.6, 1.5, 1.5] )
	),
	New Column( "N Rows",
		Numeric,
		"Continuous",
		Format( "Best", 12 ),
		Set Values( [446, 446, 446, 446] )
	),
	New Column( "Rate",
		Numeric,
		"Continuous",
		Format( "Best", 12 ),
		Formula( (100 * As Column( "N(" || Char( :MAXRESULT ) || ")" )) / :N Rows ),
		Set Selected
	)
)
					
				
			
			
				
	Jim