You will be given a definition of a task first, then some input of the task.
This task involves annotating the answer type to a given question that involve some kind of complex reasoning (including numerical reasoning). Note that the questions require looking at more than one part of the passage to answer. There are 3 possible answer types (i) spans, (ii) numbers and (iii) dates. If the answer can be found in the passage, label it as "span". If the answer is a number, label as "number". Similarly, label "date" if you think the answer to the given question is a date.

Passage: Over the years the city has been home to people of various ethnicities, resulting in a range of different traditions and cultural practices. In one decade, the population increased from 427,045 in 1991 to 671,805 in 2001. The population was projected to reach 915,071 in 2011 and 1,319,597 by 2021. To keep up this population growth, the KMC-controlled area of has expanded to in 2001. With this new area, the population density which was 85 in 1991 is still 85 in 2001; it is likely to jump to 111 in 2011 and 161 in 2021.
Question: Which year is projected to show the greatest increase in population from 10 years prior?
Output:
date