It depends on how you want to skew the numbers. If you want to go for the emotional impact, you take the 2.5% as the basis. But if you look at it in reality, you see that 2.5 men out of 100 will die from it compared to 8 out of 100. The difference is 5.5%. (I said 6% before because I just glanced at the graph and couldn't remember the exact height of the bar).
Too many people who have an agenda do the same type of number crunching you do. I am surprised that they don't look at the first group and say there is a 1000% increase. (Eyeballing of about .1% compared to 1%)
And to be honest, there just isn't that much difference between 2.5% and 8%. If it were 2% compared to 30% oreven 15, then that might be worth a lifting of an eyebrow. But for the oldest group they recommend - it is about only a 3% higher risk - from about 1 in 100 to about 4 in 100. I don't know if that is statiscally significant. It wouldn't seem that it is - but I never paid much attention to the statistics I had to take. But still, it seems very small percentage of risk compared to the amount of time and money required by the screenings but more for the surgeries - all of which eventually come out of other people's pockets - either taxes or higher premiums. And we haven't even mentioned the errors involved in the screening process that may produce false results.
That's way statistically significant. And the odds aren't for dying, they're for having a 3cm size or larger aneurysm of this sort. For a cheap $300 you can find out if you have a condition that'll eventually abruptly kill you. And if you're a 60 year old former smoker the chances are 1 in 16 that you do. When I hit the age, I'll fork over the $300. Maybe you don't fit the category. Or maybe peace of mind isn't worth it to you. C'est la vie.
To get errors in the screening process, if you're talking about the actual sonogram, would require your sonographer to be blind. The diameter of the aorta is measured, it's either normal, borderline enlarged or there's an aneurysm.
P.S. I've never met a blind sonographer.