Because the personal aspect of your quote is insignificant!
The only aspect of your quote which is about YOU and your driving experience is your past accidents and the "supposed" no claims bonus.
Your quote is more affected by factors like your car, your location, last year's theft statistics, etc.
The personal aspect of your quote is insignificant!
The insurance company quote is primarily based on how much of a risk they think you will be in the upcoming year.
Now, whilst one more year of proven safe driving is in your favour, there's a whole host of other parameters that may have changed from their persepctive.
Also, remember that inflation also affects everything - including insurance prices - the personal aspect of your quote is insignificant!