Help with data for a line chart

Hi this is school related. I have attendance data that comes in weeks column by column.

example below. The first column is the student, the following columns are the weeks showing the percentage of attendance for that week.

I want a line graph or bar chart it to show week as the X and percentage as the Y. The year groups will be the legend showing the average attendance of each year group per week. I havew this data linked in off another table. 

I'm working in the idea i need to change the layout as follows

I can't change how it comes out of the database/MIS. I need to change it in BI