15. The National Assembly may apply a minimum time coverage lower than indicated in the table, but not lower than 14 % for fixed measurements and 6 % for indicative measurements provided that it is satisfied that it can be demonstrated that the 95 % expanded uncertainty for the annual mean, calculated from the data quality objectives in the table according to ISO 11222:2002 — “Determination of the uncertainty of the time average of air quality measurements” will be met.