These are a few corrections for your writing.
all services have experienced an alterationAvoid using this sentence. This is like the hackneyed sentence. As we can see, there are changes certainly.
This is the alternative overview:
OVERALL, IT IS IMPORTANT TO NOTE VISITORS HAD FELT MORE PLEASURABLE THAN THE PREVIOUS YEAR.
Turning to the body paragraph, you describe the data separately based on years. I suggest you compare the figures in the different years,
Initially, more visitors claimed the customer service was satisfactory at 45%, compared to other figures
INITIALLY, THE VISITORS FELT SATISFIED WITH THE SERVICE, REPRESENTING AT 64% FOR TOTAL OF CATEGORIES' PERCENTAGES IN SATISFACTION VALUES (EXCELLENT, GOOD, AND SATISFACTORY).HOWEVER, THEIR ASSESMENT CHANGED IN THE FOLLOWING FIVE YEARS, MARKED WITH AN INCREASE BY A FIFTH OF TOTAL RESPONDERS.
Turning to 2010 CIRCUMSTANCE, the highest percentage was experienced in CLASSIFICATION "good" at twice higher ...
This was in contrast to the figure for both poor and very poor
(I did not get the point of this sentence. Remember, your overall aim in the Writing Test is to COMMUNICATE with the examiner, not to 'impress' the examiner. Actually, their percentages dropped, not the categories) seeing a decrease, with higher proportion shown in the former.