Historical clue formulations

• Invariably — 2025-03-30
• Without fail — 2021-06-27
• Unfailingly — 2018-09-04
• Ever — 2013-03-17
• Irving Berlin classic — 2003-09-09
• 1990's Coca-Cola slogan — 1999-04-16
• Irving Berlin classic — 1998-04-09
• Inevitably — 1997-04-30