When you view individual responses in the Analyze Results section, responses are ordered by Last Modified (date and time). This time stamp updates every time someone edits a response (you or the respondent), so you may notice that the order of your responses may change. For example, in a survey with 30 responses, if you edit the response for Respondent #1, that response will be updated as Respondent #30.
In contrast, when you export responses data in XLS, SPSS, or CSV format, responses in the spreadsheet are ordered by start date. This order won't change, even if someone edits a response.
To align your spreadsheet with the order of responses in the Analyze Results section, sort your spreadsheet by the EndDate column so the results go from the earliest modified date/time to the most recent modified date/time.