How do I make a cumulative % line with below data?

There are quite a few aspects to the challenge.

First, you'll need to define an order on the buckets.  This will allow you to display the visual correctly AND calculate the cumulative % correctly.

One way to do this is to extract the distinct bins to a table.  You could construct the table manually (in excel) or experiment in Power Query but what you want is a 2 column table with

Bin   Index

0-2     1

3-5     2

and so on

You then create a relationship between the bins(buckets) on both tables.

Next, get a slicer for Month-year.

Then make sure that you can show Qty on a visual with buckets in the correct order.  Use 'Sort by Column' feature to sort buckets by the Index.

If you do this succesfully, write a measure to work out the cumulative quantity.  Use a table visualisation to test this.

From there, use the measure you've just written to construct a % change measure.

Then put it all together on the Line and Clustered column chart.

If i was you i'd change the test data to something which shows the changes more distinctly because 1,4,5 are very small compared to 667 so the chart will have a large initial value then flatline.