With one major exception, the US auto industry is quite fragmented. The top 5 car and Crossover/SUV models account for under 30% of 2014 sales. These are by far the two largest segments of the US auto industry. The exception is pick-up trucks where the top 5 models make up 90% of sales. The Marimekko Chart below summarizes sales by model within each segment and provides a market map of the US auto industry. The data comes from Good Car Bad Car. Notice that model segments are shaded based on the country of origin of the manufacturer. The manufacturers of the best selling car models are from Japan (shaded in green) while the manufacturers of the best selling pick-ups are from the US (shaded in brown).
The Marimekko chart allows you to create a two-dimensional market map. Here we have sales by model within each market segment. The segment widths are proportional to the size of the segment and the area assigned to each model is proportional to model sales. I grouped all models with sales of under 150,000 units into the 'Other' category in each segment. I also used colors and shading to distinguish among and group models. All models from Japanese manufacturers are in shades of green, US in shades of brown, Korea in shades of blue and Germany in purple. The market map is an excellent chart to show the degree of market fragmentation. The chart is in SlideShare below to download and study more closely: