Devos Inc. sells bulk stationery supplies to businesses in El Paso. They have 4 product lines. Binders, Pencils, Pens, and Desks. Each of the Units represents one bulk order for a given product line. The selling price for each bulk unit is as follows: The selling price for each bulk unit is as follows: Item Price Binder $25 Desk $100 Pencil $8 Pens $12. The cost of goods sold for each bulk order is as follows: Item COGS Binder $12 Desk $40 Pencil $3 Pens $4. Their total variable selling expenses are estimated to be $10,000 for the year and are assigned proportionally to each product line based on its sales mix. Fixed costs for the year are estimated to be $6,800. Monthly selling data for each product line can be found here:

Monthly Sales	Product Line	Units
Jan-20	Binders	27
Jan-20	Pens	83
Jan-20	Desks	94
Jan-20	Pencils	95
Feb-20	Desks	11
Feb-20	Binders	15
Feb-20	Pencils	36
Feb-20	Pens	81
Mar-20	Desks	4
Mar-20	Binders	16
Mar-20	Pencils	56
Mar-20	Pens	99
Apr-20	Desks	11
Apr-20	Binders	22
Apr-20	Pencils	66
Apr-20	Pens	105
May-20	Desks	10
May-20	Binders	14
May-20	Pencils	75
May-20	Pens	105
Jun-20	Desks	4
Jun-20	Binders	15
Jun-20	Pens	76
Jun-20	Pencils	90
Jul-20	Desks	7
Jul-20	Binders	19
Jul-20	Pencils	53
Jul-20	Pens	101
Aug-20	Desks	13
Aug-20	Binders	24
Aug-20	Pencils	32
Aug-20	Pens	108
Sep-20	Desks	3
Sep-20	Binders	10
Sep-20	Pencils	90
Sep-20	Pens	93
Oct-20	Desks	8
Oct-20	Binders	11
Oct-20	Pencils	35
Oct-20	Pens	101
Nov-20	Desks	7
Nov-20	Binders	28
Nov-20	Pencils	67
Nov-20	Pens	73
Dec-20	Desks	8
Dec-20	Pencils	14
Dec-20	Binders	25
Dec-20	Pens	101

if the total sales dollars of all 4 product lines combined increases by 25%, what will be the percentage change in operating income?