MILAN — Silvio Berlusconi’s TV company Mediaset, which controls Italy’s three largest commercial TV channels and its largest advertising agency, showed a 2% drop-off in net profit earnings in 1996, along with a complete discharge of all its debt.Mediaset’s board on Thursday reported that net earnings fell to 445 billion lire ($268 million) from $274.5 million a year earlier, while sales rose 6.1% to $1.8 billion from $1.7 billion in 1995. Pretax profit rose 45% to $504 million, and the per-share dividend to private investors rose 11% to 125 lire (12¢). Its debt, which had reached $390 million at the end of 1995, has been totally discharged, due primarily to a stock float on the Milan market and the sale of nearly 50% of its shares to Italian and international shareholders including Kirch Group, French pay-TV giant Canal Plus and Saudi prince al Waleed ben Talal. Mediaset is still controlled by Berlusconi’s holding company Fininvest with a stake of about 50%. Mediaset also said that it has seen a strong sales growth in the first few months of 1997 and that commissioned advertising at its Publitalia unit rose by 10.4% in the first months of 1997 against the same period a year earlier. The group said net profit at parent level rose by 53% to $224 million. Analysts, however, are cautious about Mediaset because of uncertainty over Italian television regulations now being discussed in Parliament. The proposed rules could force Mediaset to convert one of its three TV stations into a satellite channel.