Mobile Data Usage Disparities

[Blue2k]

Hello,

Using power bi I am trying to find the largest disparities between users monthly date usages. I am having trouble trying to get this. 
 
Here is an example data set, I am not sure if I should add a column to put the calculations in. I want to be able to have show through a visual too. 

Username	Data usage (GBs)	Month
csherborn0	36	Jan
llorenzetti1	84	Jan
thuddlestone2	86	Jan
tleseka	56	Jan
csherborn0	80	Feb
llorenzetti1	72	Feb
thuddlestone2	63	Feb
tleseka	69	Feb
csherborn0	92	Apr
llorenzetti1	83	Apr
thuddlestone2	74	Apr
tleseka	66	Apr

Any help would be great!

[Blue2k]

I got this to work for the table that I put up there. This is what I want! How would I change the source to the files that I am using? 
And would I have to get rid of anything else in the text?

[Vijay_A_Verma]

Get the data of your source in PQ.

Select entire table and do a changed type to set data type.

Open Adavanced Editor and paste following code after Changed type step (don't forget comma after Changed type step)

    #"Grouped Rows" = Table.Group(#"Changed Type", {"Username"}, {{"Max", each List.Max([#"Data usage (GBs)"]), type nullable number}, {"Min", each List.Min([#"Data usage (GBs)"]), type nullable number},{"Diff", each List.Max([#"Data usage (GBs)"])-List.Min([#"Data usage (GBs)"]), type nullable number}})
in
    #"Grouped Rows"

[Vijay_A_Verma · Accepted solution]

See the working here - Open a blank query - Home - Advanced Editor - Remove everything from there and paste the below code to test

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("bY8xDoMwDEXv4pkBEprAyMLAFSIGKJaoiBIU3KWnbzIABrF4eE9fTzYG3tuMYfTB5ZCBVPF0g4M+M2CtD+h+SPQpIq5K5mj+TpPFjbxDkSQfUhS4DJG8OL6UqnRaHJ9KWjB3LynJ5VFSNcOXUp1WzRoef5LM3Uu65PIsqR33fw==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Username = _t, #"Data usage (GBs)" = _t, Month = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Username", type text}, {"Data usage (GBs)", Int64.Type}, {"Month", type text}}),
    #"Grouped Rows" = Table.Group(#"Changed Type", {"Username"}, {{"Max", each List.Max([#"Data usage (GBs)"]), type nullable number}, {"Min", each List.Min([#"Data usage (GBs)"]), type nullable number},{"Diff", each List.Max([#"Data usage (GBs)"])-List.Min([#"Data usage (GBs)"]), type nullable number}})
in
    #"Grouped Rows"