Outside of occupational hats (hard hats, etc.), the military is probably the last real holdout of hat use in the US. I would say the ball cap is pretty common

Outside of occupational hats (hard hats, etc.), the military is probably the last real holdout of hat use in the US. I would say the ball cap is pretty common among farmers. Suppliers hand out their branded hats like candy. Not to mention baseball players themselves, who pretty much also wear the style of hat while in a professional setting.