Passage: On February 1, 1994, the company filed a sound trademark application for the distinctive sound of the Harley-Davidson motorcycle engine: "The mark consists of the exhaust sound of applicant's motorcycles, produced by V-twin, common crankpin motorcycle engines when the goods are in use". Nine of Harley-Davidson's competitors filed comments opposing the application, arguing that cruiser-style motorcycles of various brands use a single-crankpin V-twin engine which produce a similar sound.  These objections were followed by litigation. In June 2000, the company dropped efforts to federally register its trademark.

Question: What did Harley Davidson do in June of 2000?
dropped efforts to federally register its trademark