Final answer:
By 1913, the United States had emerged as a major industrial power, although the exact percentage of global industrial output is not specified for that year. Indicators from surrounding periods suggest the U.S. held a significant share of the world's industrial production.
Step-by-step explanation:
By 1913, the United States had undergone an immense transformation, burgeoning into a major industrial power and overshadowing the industrial output that the United Kingdom had dominated in the previous century.
Although specific figures for the year 1913 are not provided, indicators from various points in history illustrate America's industrial prowess.
In particular, during World War II, the United States' production capabilities became so efficient and expansive that it was able to produce nearly half of the world's armaments, contributing to its significant role as the "arsenal of democracy."
Additionally, by the end of World War II, the United States was manufacturing 50% of all manufactured goods globally, despite only having 5% of the world's population.
This statistic, although from a slightly later period, helps contextualize the enormous growth of U.S. industrial output around the early twentieth century.
Evidence suggests that by 1900, America had already surpassed European production, and by the 1940s, especially during World War II, it clearly dominated global industrial output.
The impressive growth of industries such as steel, which saw production rise from thirteen thousand tons in 1860 to over twenty-four million tons annually by 1910, exemplifies the massive scale of U.S. industrialization.
Therefore, while the exact percentage for 1913 is not specified, the trajectory of U.S. industrial growth indicates it was already a significant portion of global output, well on its way to reaching its mid-century peak.