The line graphs illustrate that British parents waste their money on their children’s sporting activities and the participation of British children in three different sports from 2008 to 2014.
It can be seen clearly from the chart that the average monthly money which British parents spend on the children’s sports increased steadily, meanwhile the number of children who took part in football, athletics, and swimming rose.
In 2008, parents in British paid 20 pounds for their children to participate in sporting activities. There was a dramatic growth in the amount of money which the parents spent on their children’s sports in British over the period of four years, approximately 31 pounds.
The number of children taking part in football and athletics remained stable, while there was a slight increase in the attendance of children in swimming, about nearly 7,5 millions, 0,5 millions and 2,4 millions respectively between 2008 and 2010. In the next four years, the participation of children in football and swimming grew moderately, around 9 millions and 4 millions. Besides, the number of children attending athletics climbed significantly, approximately 5 millions, and was as high as swimming from 2010 to 2012. 
The two line graphs illustrate that British [ 1] parents’ spending [ 2] waste their money on their children’s sporting activities, and the participation of British children (in millions) in three different sports from 2008 to 2014.
[ 3] It can be seen clearly from the chart that Overall, the average monthly money amount which British parents spend [ 4] spent on the children’s sports increased steadily, meanwhile the number of children who took part in football, athletics, and swimming rose.
In 2008, parents in British Britain paid 20 pounds for their children to participate in sporting activities. Then, there was a [ 5] dramatic steady growth in the amount of money which the parents spent on their children’s sports in British that spending over the period of following four years, to approximately 31 pounds.
The number of children taking part in football and athletics remained stable, while there was a slight increase in the attendance of children in swimming, about nearly 7,5 millions, 0,5 millions and 2,4 millions respectively between 2008 and 2010. In the next four years, the participation of children in football and swimming grew moderately, around 9 millions and 4 millions. Besides, the number of children attending athletics climbed significantly, approximately 5 millions, and was as high as swimming from 2010 to 2012. [ 6]
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[ 1]: Note the position of the apostrophe.
[ 2]: “waste” is the wrong word! Sport is not a waste of money!
[ 3]: Avoid waffle/fillers in IELTS writing, especially in task-1.
[ 4]: That period is all in the past.
[ 5]: “dramatic” is too strong for that graph.
[ 6]: That is clumsy and too long. Say something like:
The number of participants in football and swimming started at around 8 million and 2 million, respectively, and while the former rose to about 9 million, the latter increased to almost 4 million. However, the line for athletics, which started at only 1 million, ….
Try to finish that last sentence, fix the essay, and post the revised version below.
The two line graphs illustrate British parents’ spending money on their children’s sporting activities, and the participation of British children in football, athletics, and swimming from 2008 to 2014.
Overall, the average monthly amount which parents in Britain spent on their children increased steadily, meanwhile the number of children taking part in three different sports rose.
In 2008, British parents paid 20 pounds for their children to participate in sports. These figures climbed stably, reaching approximately 30 pounds in 2014.
The number of participants in football and swimming was 8 million and 2 million respectively. There was a steady rise in the participation in these sports, about 9 million in football and 3 million in swimming. Besides, athletics had only 1 million people attending in 2008. The attendance in that sport increased dramatically to around 5 million in the following 6 years and exceeded the numbers taking part in swimming in 2011.
If you want me to continue to help you, please use what I suggested above.