Silver/Gray vehicles. An automotive colors study description reads: "Unobtrusive and seeks to blend in". The least amount of awareness factor for other drivers to register visually and be cognizant of. Fairly unpopular compared to nearly all other colors unless it's a traditional Porsche, of coursha. About 1/3 of all Porsche production is "Arctic Silver", did you know that? There's another Porsche silver though, "Polar Silver", which is a special order color that costs like $3K extra to get. It's so fine a metallic, and so deep looking you'd think you could dip your hand right into it.
Silver Smoke Gray was rare as 22GT stated, but for good reason.
Gray cars (and green) made a huge leap in popularity in the mid nineties and that continues today. Green has the "Green" connotation of earth friendly. Gray I believe became popular during that economic boom when people were buying new cars but didn't want other folk to think they were being flashy. I used to order all the BMW, Porsche, and Acura cars for a big dealership. I could order whatever I wanted and the trick was to order the colors that were in demand and sold quickly
. I remember one particular BMW color, Aspen Silver, that was really a gray metallic with a pinkish tint to it. I tried a few of those in the 5 series and found out some women thought it was pretty, but men hated it.
Those cars were hard sells that sat on the lot longer than any others.