SVGI’ve updated my marketshare spreadsheet for June 2010 charting the percentage of web users who can view SVG and Canvas: 41.49%
Note that I added "Canvas" back into the title of these blog posts, now that it is public that IE9 is supporting the HTML5 <canvas> element. I've also added SVG-as-an-image (usable inside <img> or as a CSS background-image), since that's something that seems likely to be supported soon by all browsers (Firefox 4, IE9).
P.S. This figure does not take into account any user that has a SVG plugin installed or authors who have used the excellent SVG Web or excanvas shims, so this is really a worst-case number.