Which year had a significant difference when comparing the median age from 1911?

The median age of a population can reflect various socioeconomic factors, including health care improvements, changing birth rates, and migrations, among others. In the context of the question, the year 2011 is significant when compared to 1911 because it marked a substantial shift in demographic trends and life expectancy.

From 1911 to 2011, there were dramatic changes in the distribution of age within populations in many countries. The 20th century experienced a decline in mortality rates, advancements in medicine, and increased living standards, which contributed to a notable rise in the median age. Specifically, by 2011, many countries had populations that were aging due to lower birth rates and longer life expectancies.

In contrast, other years such as 1951, 2001, and 2005 may show some changes in median age, but they do not reflect as marked a shift over the century as seen in 2011. Therefore, 2011 serves as a pivotal point for illustrating how demographic structures shifted over time, making it the year with a significant difference when compared to 1911.