Final answer:
By 1890, the British Empire had grown significantly and Queen Victoria's subjects possibly made up a considerable percentage of the global population, especially with nearly 300 million subjects in India alone.
Step-by-step explanation:
During the late 19th century, particularly by 1890, the British Empire had expanded significantly under Queen Victoria's reign. Growth in the British Empire coupled with industrialization contributed not only to a rural-to-urban shift within Britain but also to a demographic change globally as people moved from colonies to the metropolitan core and cities expanded. While urbanization progressed rapidly within Britain, the Empire overseas burgeoned.
The British colonial empire in the aftermath of World War I was vast, covering approximately 25% of the Earth's land surface. Considering the scope of British control and influence, Queen Victoria's subjects would have made up a significant proportion of the world's population during her reign. In India alone, nearly 300 million Indians were ruled by the British. This figure does not account for the population in other colonies which were spread across the globe, from Africa to the South Pacific.
Estimating the exact percentage of the global population who were Queen Victoria's subjects around 1890 is complex due to the varying definitions of subject status and incomplete historical demographic data. However, the sheer size of the British Empire suggests that a substantial portion of the world's population fell under her sovereignty. Considering the Indian subcontinent's population and adding in other territories, it is plausible that Queen Victoria's subjects could have constituted a double-digit percentage of the global population.