Businesses with 3-19 employment are randomly selected based on further strata, with the sample allocated amongst SIC sections based on turnover proportions.
Dewisir busnesau gyda chyflogaeth 3 i 19 ar hap ar sail strata pellach, gyda’r sampl sy’n cael ei dyrannu mewn adrannau DDS yn seiliedig ar gyfrannau trosiant.