29/01/2004 (Agence Europe) - Annual growth of the M3 monetary mass in the euro-zone has slowed slightly according to data published on Thursday by the European Central Bank (ECB). Growth stood at 7.1% in December, against 7.4% the previous month. During the past three months, M3 posted 7.6% growth against 7.7% in September; October and November. The progression of private sector credit stood at 5.4% in December against 5.6 % the previous month.