When was the last time that America was great?

The 'Let's make America great again' phrase is undoubtedly linked with Trump and the MAGA movement, yet Ronald Reagan was the first one to use the phrase during his 1980 presidential campaign. So I want to know when you believe that America was great for the last time. As according to Reagan and Trump, it hasn't been great since the 1970s or happened to not be great during the tenure of a Democratic president but flipped back under the Republicans for some reason.