I asked Goog's for enterprise value of the sector as a percentage of total market in all 4 situations, so it's not exact because enterprise value isn't available back to the 1800s, but it should be ballpark assuming the overall picture is accurate.

In terms of infra spending as a percent of GDP, 1880s railroads were at 5-6% at peak while AI is estimated to reach 3+% in a year or two.