Description of retail_x_of_y

       { RETAIL_YEAR_NUMBER ( dtexpr [ , is_restated ] ) )
	| (RETAIL_QUARTER_OF_YEAR ( dtexpr [ , is_restated ] ) )
	| (RETAIL_MONTH_OF_YEAR ( dtexpr [ , is_restated ] [ , index_by ] )) 
	| (RETAIL_MONTH_OF_QUARTER ( dtexpr [ , is_restated ] ))
	| (RETAIL_WEEK_OF_YEAR ( dtexpr [ , is_restated ] ) )
	| (RETAIL_WEEK_OF_QUARTER ( dtexpr [ , is_restated ] )) 
	| (RETAIL_WEEK_OF_MONTH ( dtexpr [ , is_restated ] ) )
	| (RETAIL_DAY_OF_YEAR ( dtexpr [ , is_restated ] ) )
	| (RETAIL_DAY_OF_QUARTER ( dtexpr [ , is_restated ] ) )
	| (RETAIL_DAY_OF_MONTH ( dtexpr [ , is_restated ] ) )
	| (RETAIL_DAY_OF_WEEK ( dtexpr [ , is_restated ] [ , index_by ] )
      }