Cost related to shipping and registering a recently purchased car

Hi there! We shipped our 2001 Acura 18 months ago and found it less expensive than we had anticipated because of the age of the car. We now want a second car on the island and opted to buy stateside a 2010 Acura (very reliable vehicles) and did not register it before shipping. Before we made the purchase, we tried to find out all the costs involved. We know about the import tax, shipping, marbete, insurance etc, but today, when paying annual fees for the car we already have here, we ran into something new called derechos anuales. I speak Spanish fairly well, but I cannot understand on the official govt website how the derechos anuales is figured. Heck, it’s hardly mentioned anywhere. What exactly is it and does the value of the vehicle affect how much we pay for it? Are there other taxes or fees to pay that use the car’s value as a factor? Sales tax? Thanks very much!