All the trays I know are arranged so that the cutlery lies at 90 degrees to the opening, so handles towards the person who opens the drawer. I don't think that can be particularly American. Is this some fancy high end kitchen design type tray?
As to numbers, I read a piece of research somewhere about lefties, which compared the distribution of human handedness with that of chimps. Apparently, among chimps, about 40% are lefties, 40% righties, and 10% either ambidextrous or ambisinistrous (that's clumsy, with no dominant hand). (I may be wrong about the exact proportions, but you get the idea.) This suggested that humans might not be inheriting lefthandedness, but righthandedness. So the research went on to examine all available members of families with one known lefty. And among the blood relations, the proportions were like those of the chimps. There would be a suggestion that lefthanders would be more flexible in hand use than those who have inherited righthandedness (as opposed to righthanders in lefthanded families, who might also be flexible).
Everyone needs lefthanded nailscissors for cutting their right hand nails. Curiously, I am just watching someone explaining a pair of scissors designed to be used in either hand, and getting it wrong. It is not about the handles. It is about which way the blades cross. With righthanded scissors, the blade on the right lies on top when you put them down, and the blades are pushed together during use. A lefthander gripping these scissors pushes the blades apart, so they don't cut properly. Lefthanded scissors have the left blade on top, so the blades push together when a lefty uses them. I researched this for school, and bought my own for the children to use, with strong words about the right handers not using them. It took years before the school caught up with the idea, even though the teacher in charge of ordering kit was left handed.
In classes I taught the numbers of lefthanders varied between 2 to 6 out of 30, as far as I remember. I'm ambi enough to be able to show children how to write lefthanded, and to know that the instructions for a lefthanded pencil grip were utterly rubbish. You know the weird way left handed bank clerks (and there are a lot of them) hold thier pens, all twisted round like Olivier's arm in Richard III. Not quite as bad as that, but they demanded that the pencil be held at the same angle as if held by a right hander, with the wrist turned back towards the left. Not possible. The idea was that the writing implement was pulled across the paper rather than pushed, but took no regard of anatomy!
Googling suggests that the proportion of lefthanders is about 10%, which would suggest that about 25% or so do not inherit righthandedness. In interactive sports, apparently, lefthandedness is as high as 32%. These proportions are higher than in the past. Apparently. There was a bad bit of research done on ages at death done by finding the proportions of lefthanders in different cohorts, and showing that the older the group, the fewer the lefties. Totally ignoring the way lefties were forced to switch hands. Like the King of the Speech, where the switching may have been implicated in his stammer.
I sometimes wonder how strict righthanders manage with screwdrivers and other tools in odd corners. They must be at a much greater disadvantage than lefthanders.