Last week, I stumbled across a preview of the cover for the April issue of Vogue. The issue features Michelle Obama — the second Vogue cover for the First Lady. After forcing myself to look away from her toned arms and stylish bangs, I did a little digging into sales. We all love the first lady, but I wanted to know if she sells magazines.

Does she ever! As it turns out, Michelle Obama’s previous cover sold 560,000 copies, and was one of the best-selling issues of all time. It looks like this repeat performance may be a bit more calculated than I had initially thought.

What’s more puzzling than Michelle Obama raking it in for Vogue are those that are not. Take Rihanna, for example. At 25, she is already one of the best-selling artists of all time and she recently snagged her 12th number one single, the name number as Madonna. In 2012, Forbes ranked her the fourth most powerful celebrity and Time named her one of the most influential people in the world. Say what you want to about her, but Rihanna has been on fire these past few years.

Except, apparently, when it comes to magazine sales.

Rihanna’s November 2012 Vogue cover, the same year as the Forbes and Time accolades, was one of the worst selling issues of the entire year. It sold just 227,000 copies, less than half of the first lady’s cover sales.

Other confusing cover star stats for 2012:

• Best-selling Cosmopolitan Issue – Scarlett Johansson in January
• Worst-Selling Vogue Issue – Olympics-themed in June with Hope Solo, Serena Williams and Ryan Lochte (in bathing suits!)
• Worst-selling Elle Issue — A naked and pregnant Jessica Simpson in April
• Worst-selling Vanity Fair Issue — Kate Moss in December
• Best-selling Marie Claire Issue — Zooey Deschanel in May
• Katy Perry covered the best-selling Elle in September and the worst-selling issue of Teen Vogue in May

It’s clear that popularity, past cover sales and even of-the-moment hype have no clear correlation to great magazine sales. With figures like this, a focus on engaging and exciting content is key to ensuring great sales — no matter what beauty is gracing the cover.