Rank the following countries by population size.
1. India - According to data from the United Nations, India has an estimated population of 1,366 million people as of 2019.
2. Argentina - According to data from the United Nations, Argentina has an estimated population of 44.94 million people as of 2019.
3. Australia - According to data from the United Nations, Australia has an estimated population of 25.36 million people as of 2019.
Australia, India, Argentina
Below is an instruction that describes a task, paired with an input that provides further context. Write a response that appropriately completes the request.

### Instruction:
Rank the following countries by population size.

### Input:
Australia, India, Argentina

### Response:
1. India - According to data from the United Nations, India has an estimated population of 1,366 million people as of 2019.
2. Argentina - According to data from the United Nations, Argentina has an estimated population of 44.94 million people as of 2019.
3. Australia - According to data from the United Nations, Australia has an estimated population of 25.36 million people as of 2019.