The US standard (if you get paid holidays at all) is 10 days in most workplaces. 15 is relatively generous. I did work at a University that gave some employees

The US standard (if you get paid holidays at all) is 10 days in most workplaces. 15 is relatively generous. I did work at a University that gave some employees 24 days plus holidays, which was fantastic, and institutionally tolerable because the work load of the University was so much lower in the summer months. But while the benefits were good, the wages were about 60% of the market rate.