The line graph gives information about the proportion of rivers in UK, which had good chemical outcomes, from 1990 to 2002.
Overall, in all mentioned places, in the UK had the good chemical rose by 2002, only Wales had this percentage down. Moreover, the percentage of good chemical quality in Wales and Northern Ireland were quite high, the reverse is true for England and Scotland.
Focusing on the river water quality of Wales and Northern Ireland first, the states stood at the same percentage at 95 in the 9 years. After that, they experienced changes for 2000 about 91% before the data on Northern Ireland increased slightly and remained stable at 95% at the end of the period. As a contrast, Wales decreased gradually to 80% in 2002.
As for the quality of river water in other remaining states, England show a gradual rose from 42% in the first year to 69% in 1996, after which it underwent a decrease to 30% in next year before grew gradually in the last year. Scotland had the quite same percentage of quality of chemicals in England. It rose enormously and remained valuable at 30% in 1996 before decreased back at around 50% and fell at 40% in 2002.