The graph shows the changes in the value of the euro against the US dollar between January and October of 2010.
In January and February, the value of one euro fluctuated between $1.38 and $1.45. By March, this fluctuation stopped and the value settled down. During the month of April, the value of the euro plunged. It reached its lowest point of $1.20 at the end of April. During May, the value of the euro recovered. Slightly at first, but then more sharply between the middle and the end of the month.
In conclusion, that graph shows that the month of June, the value of the euro remained constant at a value of $1.37. But this changed in July, when the value soared from $1.37 to $1.66. In August, this dramatic rise levelled off. This levelling off continued into the month of September, where the euro's value peaked at $1.68. But during October the value fell back, finishing the month with a value of $1.47.