The line graph illustrates the proportion of the quality of chemicals in rivers in the UK from 1990 to 2002.
Overall, it is obvious that all the states in the UK had the good chemical rose after 12 years, only Wales had this percentage down. Besides, the percentage of good chemical quality in Wales and Northern Ireland were quite high, converse to England and Scotland had a quite low percentage.
The river water quality of Wales and Northern Ireland had the same percentage at 95 in the first 8 years. After that, they experienced volatility for 2000 about 91% before the data on Northern Ireland increased slightly and remained stable at 95% at the end of the period. Contrast to, Wales had tended to decrease gradually to 80% in 2002.
Addition, the quality of river water in England commenced to rose gradually from roughly 42% in the first year to approximately 69% in 1996, after which it underwent downed gradually 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 gradually and remained valuable at 30% in 1996 before jumped back at around 50% and forth erratically at 40% in 2002. Moreover, these rates also cut out at 40% in 19988.