An "all-time low" is the lowest level something has ever reached in its recorded history. It signals an extreme drop in performance, price, mood, or quality compared to any previous point.
Late night television is ready for someone like me... standards have gone to an all-time low. Howard Stern
Ashes to ashes, funk to funky We know Major Tom's a junkie Strung out in heaven's high Hitting an all-time low. David Bowie
The world at large is less inequitable today than at any time in history. Number of people in abject poverty, as a percentage, is at all-time low. Bill Gates
Today's stock market actually hates technology, as shown by all-time low price/earnings ratios for major public technology companies. Marc Andreessen
My all-time low is 62 at Bel-Air, but it was in match play, and I had two putts given to me from four feet. I'm playing only about once or twice a month. Full-time job. Full-time father. Full-time blonde. Jack Wagner
Spending on programs such as national defense and funding the operating budgets of all federal agencies represent only 39 percent of our yearly budget, an all-time low. Paul Gillmor