A company's revenue (in $\text{Rs. lakhs}$) for five years is listed as:
* 2018 : $40$
* 2019 : $55$
* 2020 : $35$
* 2021 : $65$
* 2022 : $80$

What is the percentage increase in revenue from 2020 to 2022?

Given data values:
* Revenue in $2020=35\text{Rs. lakhs}$
* Revenue in $2022=80\text{Rs. lakhs}$

First, find the absolute increase in revenue from 2020 to 2022:

$$\text{Increase}=\text{Revenue in 2022}-\text{Revenue in 2020}$$

$$\text{Increase}=80-35=45\text{Rs. lakhs}$$

Now, compute the percentage increase relative to the base year (2020):

$$\text{Percentage Increase}=\left(\frac{\text{Increase}}{\text{Revenue in 2020}}\right)\times 100\%$$

$$\text{Percentage Increase}=\left(\frac{45}{35}\right)\times 100\%$$

$$\text{Percentage Increase}=\left(\frac{9}{7}\right)\times 100\%\approx 1.285714\times 100\%=128.57\%$$

Therefore, the percentage increase in revenue is $128.57\%$.