National Annual Rural Sanitation Survey 2018-19

Consider the following statements with respect to National Annual Rural Sanitation Survey (NARSS 2018-19):

1. This was the third National Annual Rural Sanitation Survey (NARSS 2018-19) to establish the progress over the baseline established by second NARSS 2017-18.
2. The NARSS 2018-19 is a third-party survey that has been conducted by the Independent Verification Agency (IVA) under the United Nations Development Programme.
3. The Survey used the Probability Proportion to Size (PPS) sampling methodology, which yields results within a confidence interval of 95 percent.
4. According to the Survey, about 93.1 per cent of rural Indian households have access to toilets and 96.5 per cent of these toilets are in constant usage.

Which of the statements given above is/are correct?