Final answer:
The percentage of older men holding full-time jobs has decreased dramatically since 1900. The percentage of older men who hold full-time jobs has likely not increased dramatically, and considering there is no significant long-term trend in unemployment rates, the best answer is that it has steadily decreased since 1900.
Step-by-step explanation:
The percentage of older men who hold full-time jobs has decreased dramatically since 1900.
According to the provided information, the U.S. population has increased significantly over the years, and a higher proportion of women have entered the paid labor force. However, despite these changes, there has been no long-term upward or downward trend in unemployment rates. Therefore, we can conclude that the percentage of older men who hold full-time jobs has decreased dramatically since 1900.