The chart shows how much money people spendspent on fast food per week depending on their income
says
illustrates
The first thing we can see is that people with high household income eat more expensively than ones with worse salary
You should adopt a less personal tone for this report. Also, as Dumi suggested above, there should be an overview after the introduction to state the main trends of the charts. This is my example:
Overall, hamburgers were the most popular among high and average income groups while the low income group tended to spend the most on fish and chips. Likewise, there is an increase in the consumption of pizza and hamburgers, as opposed to that of fish and chips.It's mainly showed in expenditure on hamburgers - people with high income spend 40 pences per week for hamburgers
Try to avoid redundant words in your sentences.
wherewhile these with low income spend only 15
Fish and chips were losing lost their popularity in years 1970-1985
they started to gain it rise slightly
Hamburgers are constantly getting more popular
Past tense should be used here.