The source data of the chart is in the SVG image file in a clearly readable format. You see the original numbers inside of the SVG file in the form of a list such as this:
...
1995 10.06
1996 11.75
1997 12.45
...
Content of SVG
To view the data download the SVG file itself. To do so right-click this link, and then choose the option to save: File:Platinum world production.svg. Launch any text editor. Open the downloaded SVG file with the text editor (usually; file menu, open). To see the list of data, search for the phrase id="graph1".
Edit SVG
Please, do not use a special SVG editor such as Inkscape; the readability of the database would be destroyed. You can edit the SVG file with any text editor, for example; en: List of text editors. You can view the edited SVG file in various web browsers. As of 2011, all major desktop browsers, and many minor ones, have some level of SVG support. See: en: Scalable Vector Graphics#Support for SVG in web browsers. When satisfied with your edits, upload the edited SVG file with the link labeled "Upload a new version of this file".