I want to test the ability of students to read a passage and answer questions about it. Could you please come up with a good question for the passage "The term prime minister in the sense that we know it originated in the 18th century in the United Kingdom when members of parliament disparagingly used the title in reference to Sir Robert Walpole. Over time, the title became honorific and remains so in the 21st century."? 

What allows the estimation of the duration of the term prime minister as we use today?