Please help me to check IELTS writing task 1

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The chart illustrates time spent by the UK residents of cellphone calls over a period of 7 years.
While mobiles and national and international-landline had an upward trend, the opposite was true for local-fixed line. Also, local-fixed line was the most popular of telephone calls in the UK.
In 1995, it is clear that the number of time spent on local-fixed line was twice as much as that of national and international-fixed line, at over 70 billion and about 36 billion minutes respectively, whereas on mobile calls, there was just under 5 billion minutes. Over the following 5 years, there was a gradual increase in the number of time used on local-fixed line, before decreasing to approximately 70 billion minutes in 2002.
National and international-landline calls rose slightly from 37 billion to about 60billion minutes between 1995 and 2002, compared with 70 billion minutes of local-landline in 2002. Similarly, there was a small rise in the number of mobile calls from under 5 billion in 1995 to 13 billion minutes in 1999, followed by a marked growth over the last two years, at 40 billion and nearly 50 billion minutes in 2001 and 2002 in turn.