1 A "four year high" may not mean much when it follows a 20 year decline. When manufacturing falls by 10% each year for 20 years, a 2% increase would represent a 4 year high, even a 20 year high, but would still be 96% lower than it was 20 years ago. It's much like saying it was the hottest it's been in 20 years. Maybe true, but nor as hot as it was 25 years ago.