Hopefully the 200 year span is small enough. I understand that the Silk Road was across dozens of regions and along many paths, but there must be some records from traders suggesting how much money was being made.
Followup question: How much risk was there?
“The Silk Road” is a vague concept. Popular understanding of it seems to envision trade between China and Europe with goods making a single uninterrupted journey by land or sea from one market to the other.
But in reality, the ‘silk road’ and ‘maritime silk road’ are terms which describe trade in a variety of directions within regional networks which are unified (to varying extents across time and geography) into larger networks which create linkages across the Eurasian landmass and beyond. Some goods did travel from one end of Eurasia to the other, but typically did so through a series of smaller journeys and many distinct transactions, involving a variety of price dynamics and levels of risk. u/enclavedmicrostate wrote a nice precis of the silk road in a post last week which recommends a recent monograph to dive deeper.
The period 1400-1600 partly encompasses a significant change in these trade networks. European vessels reached East Asia and began to make direct trade from Europe to East Asia, as well as open a trade route from Manila across the Pacific Ocean to the colonies of New Spain in the Americas, and then on to Europe.
Again, there are few unifying or top-level statistics in the scholarship, even within this subset of European trade. Price dynamics varied tremendously between different goods, markets/prices were extremely volatile over time. The trade involved a relatively small number of ships, and a bad year with several lost vessels could greatly alter prices. There were national differences between European kingdoms in business practices and even sailing speeds.
I can give a few statistics which indicate possible net profits and some of the risks. But note that these statistics are for slightly different time periods, and much of the profit data is slightly outside the period you are asking about.
A paper by Gasch-Tomás looking at price differentials in the period 1571-1650 indicates that the price ratio of Chinese silk between markets in Manila and New Spain was usually around 2 but in some cases as high as 3 or 4, and the ratios between New Spain and Sevilla ranged from 1.3 to 3. The dataset is small, but indicates the price in Spain could be up to 12 times higher than in Manila. This represents potential gross profits of 1100%, but net profits would be lower, with freight costs and taxes often being quite significant. Keep in mind that profits were highest for these routes at the beginning of European trade, and fell as more nations and more vessels began to trade along these routes. This data also obviously does not consider the transactions between silk producers and silk wholesalers, the freight dynamics within China, or the trade between China and Manila.
As for the risk, a paper by Claudia Rei looks at VOC (Dutch East India Company) voyages 1497-1612. The dataset includes 806 voyages over 115 years, or almost exactly seven vessels per year taking the cape route. Of these vessels 9.5% were lost or destroyed, and 2.5% of voyages were aborted and returned to their port of origin.
Europeans were a small player in Asian trade networks during this period. Competing Asian vessels (primarily Chinese merchant networks by this point) carried far more freight and did so at much more economical rates (in part because of the financial structure of Chinese maritime trade). At times the VOC derived more (or most) of its profits from trade within East Asia, such as voyages between the spice islands and China; rather than voyages back and forth to Europe. This is reflected in one interesting statistic from the VOC data, that 35.4% of the ships stayed in the East and did not return to Europe.
Moreover, these two small groupings of statistics should only be seen as perhaps 2 pieces of a 100-piece puzzle, even when looking specifically at sixteenth-century trade. Land-born trade on the actual silk 'road' was different than maritime trade. The Chinese and Japanese states pursued a variety of trade policies during this period, often interacting differently with different European powers. European geopolitics and warfare affected trade in a variety of ways, as did the the economic cycles in a variety of geographic locations across Europe and Asia.
Sources:
[edited to fix typos]