I wish more art from the Roman era had survived time. It’s obvious they not only mastered three dimensionalality but weren’t beyond exaggerating for dramatic effect. Special note on how the Muse was done with great care to accent her femininity with fashionable clothing style flattering her figure.
So much was lost due to recycling building material post-Empire along with who knows how many mosaic masterpieces. At least excavation and preservation continues at Herculaneum, Pompeii and lesser known sites still being uncovered.
You’re right of course, the overall percentage is probably low, partly as a consequence of demolition and reuse, and partly due to the sheer amount of construction the Romans did.
During the early Middle Ages, bunches of marble statuary was dragged off to lime kilns and recycled as lime mortar. What a bunch of knuckle-dragging barbarian a-holes, huh?
There’s probably still oodles of stuff buried underneath later construction.