Among the sales information of my ebooks, there is the stats of sales by country, which probably somehow represents Delphi usage around the world. Of course, this implies English speaking developers and developers with the same absolute income.... but still I think it is representative, and some of the countries in which Delphi sells at most are at the top of my ebook sales as well. Notice that the data is overall PDF sales of the various handbooks over a three months period.
You can see the list of the 22 countries with most sales here on the side of the page (from the lowest selling of the best 22, Japan, to the best selling country overall, United States). [Yes, it is not with the top at top, but that's what my online shop provides.]
Consider that United States leads with less than 20% of the sales, Germany and Australia are between 15% and 10%, Italy, United Kindgdom and Netherlands are above 5%, all other countries are below 5%, down to Japan that is well below 1%. There are countries with less than 0.5% sales, which include Turkey, Taiwan, Estonia, Barbados, Malaysia, Russia, Greece, Croatia, Jordan, Colombia, Thailand, Slovenia, and Denmark.
Another interesting element, is that All EU countries together total over 40%, which is much higher than United States even at a pro-capita (or pro-programmer) stat. It is not a surprise that Delphi has good following in Europe. Some English-speaking countries (and with high income) seems to be above their actual sales, while countries with a strong preference for localized manuals (like France and Japan) seem to fall short.
But since I don't have a lot of information regarding Delphi sales, I can infer some from my experience... but also use this ebook sales stat as in input. Maybe some component vendors can share their sales by country information, as I doubt Embarcadero is willing to do so in public.