What about things like silk, iron, bronze, marble
What? No thanks for my singular effort? Do you know how hard it is to find data? You think I had modii and ship tonnage just lying around at my fingertips?
As for you new questions, much harder to calculate, since we don't have a sense of their needs. Things made of bronze, copper, etc. don't tend to survive from Ancient times. They are too valuable and tend to be melted down and re-used again and again over the centuries. The only reason museums happen to have any Ancient bronze artifacts at all is because some were buried in tombs or sunk in shipwrecks.
So I can't answer "how often", because we don't really know "how much" they used. Although if you really want to, you can probably sit down and estimate usage in typical Roman households, army, etc., and scale that by class and population, you might get some approximation. But I am too lazy to try.
How that translates into shipping is a whole other kettle of fish, as some of the more precious things would be carried in small quantities alongside other more mundane bulk goods like wheat, wine, etc. So you can't use tonnage as a proxy the same way I did for wheat.
If you want to investigate further, I'd recommend Pliny the Elder's
Natural History, written around 73 AD, in particular
Book 33 (on gold, silver, etc.) and
Book 34 (on brass, copper, iron, etc.) and
Book 36 (on marble) and
Book 37 (on precious stones, esp. detailed on amber trade with Baltics). He talks a lot about their uses and where they're from. So you may get a sense of it.
We can say that most of the things you list are not found locally in Rome or central Italy and had to be imported, some at very long distances.
Bronze always requires trade. Bronze is a combination of copper and tin, which are hard to find, and you have to go long distances for both metals. The Mediterranean's main source of copper was Cyprus (hence the word - Cyprus = Copper island; or more properly, Copper = Cyprus metal) and the Rio Tinto region of southwestern Spain. Tin was much rarer. There was some tin in western Spain, which had been exploited at the very beginning of the Bronze Age, but were exhausted during Roman times. There was a little tin in Brittany, and larger amounts in Cornwall (England), which were also imported into the Mediterranean during Roman times.
Iron also required trade, but not as far. Although there isn't iron ore in the region of Rome itself, but there is some in Tuscany and plenty of iron ore in the Alps (esp. Noricum), southern France and Spain, which were their main sources.
By luck, a lot of marble is nearby - the marble quarries at Carrara, in northern Tuscany, were (and still are) among the largest in the world. But marble was also brought in from Egypt, the Aegean and as far away as Armenia.
Silk is impossible to calculate. But it had to come all the way from China.
And that's only scratching the surface of what they imported. There are spices, dyes and pigments, etc. Go look at Pliny to get more details. He outlines some unusual things Rome needed to import in large amounts from far away that you'd never think of - such as sand from Ethiopia, to polish the marbles.
