I really don't consider various media outlets that claim 100 million albums sales for artist to be accurate. The only 100% accurate sales informations comes from firms that actually do audits to confirm sales, like RIAA for the USA, IFPI for Europe, or in the UK the BPI. Canada has the CRIA.
The USA is 1/3 of the music market while Europe represents another 1/3. Together with Canada they comprise over 70% of all music sales, so with the sales info they provide it is easy and more accurate to gauge sales using those sites rather than inaccurate and unresearchable info thrown out there by media. Media often inflate sales. Record companies sometimes slightly inflate sales as well. Auditing firms like RIAA and IFPI do not. You get the straight facts from there. Problem with IFPI is that they do not yet certify albums released before 1994. But success in the UK is usually an indicater of success throughout Europe. If you cannot break the UK market, your most likely not going to break the Italian or French market. There for
www.BPI.co.uk/ is a good gauge for album sales in Europe before 1994. Based on this and other RIAA info, I reached the following conclusions on Genesis, Kenny Rogers, Ozzy Osbourne, Black Sabbath and of course Aerosmith.
Genesis- They might well of sold 100 million albums based on the fact their record company says so and 6,360,000 in sales in the UK alone which is 50% higher on a per capita basis than their USA sales of 21.5 million. I'd put their global total at about 90 million just shy of the 100 million mark. Realize that U2 has sold over 9,000,000 albums in the UK, 50% more than Genesis. U2s album sales in the USA(46 million) are more than double that of Genesis. Genesis has no IFPI awards at all. But then again they have only released two albums since 1994. U2 has two huge selling albums on the IFPI charts.
Kenny Rogers- sold 50.5 million albums in the USA, no IFPI awards, and only 860,000 in sales in the UK. I'd put his global sales at 60 million copies. Country does not sale beyond North America unless your name is Shania Twain.
Aerosmith-I'd put them at 83 million worldwide because of low total UK sales of 960,000. If their UK sales were on par with American sales, they would have sold 13 million there, but their lightyears away from that. The IFPI certifies two awards for them, 1 million for nine Lives, and 1 million for Big ones. Aerosmiths albums did not even crack the British top 100 in the 70s. It is only in the 90s that they have gained an international audiance and judging by their sales in Europe, this audiance is a tiny fraction of the total album sales currently.
Black Sabbath- 15 million in the USA only 500,000 in the UK. Thats right, Black Sabbath had only 5 silver(60,000) albums and two gold(100,000) albums in the UK. Chance they sold 100 million albums worldwide, not a chance in hell. Most likely only 20-25 million worldwide. Black Sabbath has huge appeal in the USA but not outside the USA. Another hardrock/metal act depending on an American audiance much like Creed does today.
Ozzy Osbourne- 27 million copies sold in the USA, only 240,000 copies sold in the UK! Thats right OZZY only has four albums that sold enough to recieve a silver award(60,000). Jeez, even U2 back in 81 and 82 before they were popular and the WAR album were able to do that. I'd put his global total at somewhere between 30 and 35 million.
OZZY/SABBATH combined at most of sold 60 million albums worldwide and thats probably a little of an overestimate.
The UK market is 10% of the world market outside the USA and acts successful in America that are unable to penetrate the UK are unlikely to be able to penetrate non-English speaking countries. I know this because of the UK British Album chart book I have and other global chart data from Billboard. Of course there are always a few exceptions, but that is extremely rare. Here is the BPI site:
www.bpi.co.uk/ .