Scanning through MSAs, here's a list of current metro areas that are more than 5% off of their peaks.
I'm using
this map from the Census Bureau for the definitions.
Metro........Peak.....2016.....Drop
Johnstown, PA........213,459.......134,732.......36.9%
Beckley, WV............178,716.......120,924.......32.3%
Wheeling, WV..........208,918.......142,982.......31.6%
Weirton, WV............167,756.......119,271.......28.9%
Scranton/WB, PA.....771,023.......555,225.......28.0%
Charleston, WV........293,631.......217,916.......25.8%
Danville, IL..............97,047.........78,111........19.5%
Decatur, IL.............131,375.......106,550........18.9%
Pine Bluff, AR..........111,955........91,962.........17.9%
Youngstown, OH.....663,178........544,746........17.9%
Buffalo, NY............1,349,211.....1,132,804......16.0%
Pittsburgh, PA.......2,768,938......2,342,299.....15.4%
Saginaw, MI...........228,059........193,307.......15.2%
Pittsfield, MA..........149,402........126,903.......15.0%
Elmira, NY..............101,537.........86,322........15.0%
Springfield, OH.......157,115........134,786........14.2%
Utica, NY...............340,670........293,803.......13.8%
Bay City, MI...........119,881........104,747.......12.6%
Cleveland, OH........2,321,037....2,055,612.......11.4%
Altoona, PA............140,358.......124,650........11.2%
Cumberland, MD......111,889........99,541.........11.0%
Muncie, IN.............129,219........115,603........10.5%
Niles, MI................171,276.......154,010.........10.0%
Flint, MI................450,449........408,615.........9.3%
Binghamton, NY.......268,328........244,094........9.0%
Farmington, NM.......130,044........118,737........8.7%
Duluth, MN.............304,528........279,227........8.3%
Ocean City, NJ........102,326........94,430..........7.7%
Mansfield, OH..........131,205.......121,107.........7.7%
Lima, OH................112,241........103,742........7.6%
St. Joseph, MO.......136,435........126,565.........7.2%
Parkersburg, WV.......98,570..........91,449.........7.2%
New Orleans, LA.....1,337,726.....1,268,883.......5.1%
Kokomo, IN..............86,896..........82,568........5.0%
Detroit is at 3.5% off its MSA high in 2000. A surprise was Huntington, WV which has enough suburban growth that the metro is only 3.6% off its 1980 peak.
Looking at 200k+ metros only:
Johnstown, PA........213,459.......134,732.......36.9%
Wheeling, WV..........208,918.......142,982.......31.6%
Scranton/WB, PA.....771,023.......555,225.......28.0%
Charleston, WV........293,631.......217,916.......25.8%
Youngstown, OH.....663,178........544,746........17.9%
Buffalo, NY............1,349,211.....1,132,804......16.0%
Pittsburgh, PA.......2,768,938......2,342,299.....15.4%
Saginaw, MI...........228,059........193,307.......15.2%
Utica, NY...............340,670........293,803.......13.8%
Cleveland, OH........2,321,037....2,055,612.......11.4%
Flint, MI................450,449........408,615.........9.3%
Binghamton, NY.......268,328........244,094........9.0%
Duluth, MN.............304,528........279,227........8.3%
New Orleans, LA.....1,337,726.....1,268,883.......5.1%