Professors who use Moodle Gradebook are strongly encouraged to back up their grades. The most common way to back up grades in Moodle is to export grades to Excel.
Also see the tutorial for Downloading and Grading Assignments if backing up grades is a part of backing up all assignments in Moodle.
1. Once logged in and at your course page, click Grades on the Navigation menu.
2. Open the dropdown menu in the Administration block under the Grade Administration section titled Export. Under this heading you will have the option to export grades as a checklist, OpenDocument spreadsheet, Plain Text file, Excel spreadsheet, and XML file.
Say, for example, you want to export to an Excel spreadsheet. Follow these steps, taken from the tutorial on how to export grades to an Excel spreadsheet (Linked here):
a. Select Excel spreadsheet.
b. On the next page you may configure settings for the export. By default, all items in your Gradebook will appear under the Grade items to be included section, but you can alter those selections to fit your needs. Under Export format options, check the “Include feedback in export” checkbox if you would like to export grade feedback with grades. Select the whether you wish to display grades as numeric (real) or percentages. Select the number of decimals that should be displayed in export grade book from the “Grade export decimal points” drop-down menu. Finally, click Download.
Note that any comments you make directly on a submission using the PDF annotating tool are not included in this download. Only those comments that are added in the feedback comments section of the grading interface are included.