Is it normal that the attributes decrease?

I just noticed that one of my drivers, with 19yo, after the race, has 1 point less in Speed attributes (Fast Corners, Slow Corners, Wet Weather). Is this normal, that some of the attributes reduce (like health, that is normal) after the race? So the driver never is going to have 100% (20)...?

It's normal, but they don't decrease by a full 1 point. They're stored as decimals in the system but we don't get to see that on the front end. So a driver with 20 in fast corners will probably be 19.9 after one race, and 19.8 after two races, so on, so forth.

From the rules and regulations handbook:

4.5 Skill atrophy

All drivers in iGP Manager have an atrophy on their skills for every race they are contracted to a team. When a driver is not employed they do not atrophy. The older a driver is, the higher the rate of atrophy will be. This represents the struggle to remain competitive as a driver ages, and in their last seasons before retirement training may be doing more to maintain their current skill levels rather than improve it. Young drivers atrophy more slowly, and as a result training can be more effective and have longer-lasting effects for them.

4.6 Skill levels

Skills are not stored in our databases as whole numbers, they are stored as decimals. They are only displayed as whole numbers for convenience and simplicity. For example, if a driver has 7.00 for stamina, and you train it by +1 prior to a race, it will then be 8.00. After the race, with atrophy factored in, it will become approximately 7.9. On the front-end this will be displayed as going from 7 to 8 and back to 7 again, but this does not mean a whole digit was lost, it simply means that the value is less than 8 and more than or equal to 7. When you hire a driver to your team, the overall level as displayed on the Staff page can be a good indicator of this. The overall rating bar for the driver shows his or her level in green, with a blue bar underneath indicating how close they are to obtaining the next level. Two drivers may both be displayed as level 4, but one is actually about 4.1 and the other can be 4.9. The actual level of a skill may not be displayed in the text on the bar, but the length of the bar underneath the number always represents the complete decimal value. Even on the smaller bars in-game, a driver with 4.9 for an attribute will have a longer bar than a driver with 4.1 for an attribute value, though both will simply say "4" in text.

oh! Thanks!! I already had read that, but I don't why, I thought it was just when the driver is older... +25...

Thank you very much!! :)