From over 16,000 people surveyed, more than half (54%) say they "do some" when it comes to
alt text for images that are important to content. The example provided did provide insight into the content and relevance of the image.
Thankfully the least number of people (10%) said they "do nothing." This is unfortunate as it is a a real accessibility problem.
22% said they "do a little." The example provided gave no insight into the content and relevance of the image, making it just as bad (possibly worse, as it costs time) than doing nothing. But I suppose at least they are aware they should be providing alt text.
14% of people said they "go all out." In the example (an image of a graph), the exact numbers shown in the graph were spelled out and the most striking fact about the graph explained. That is often the point of a graph: to emphasize a particular juxtaposition. As long as "go all out." doesn't turn into "go too far" (use your own good judgement), this is the ideal way to go.
For more information, the A11Y Project says:
altattribute is meant to help users not miss any content, so make sure your text is helpful to anyone not seeing the image. These could be assistive technology users or users of a mobile with images turned off (to save data, for instance).
Full, real time results for this poll and all past polls are in the polls archive.