How to find the Percentage change compared to Previous Month in Tableau

Identifying and highlighting the percentage difference of a measure compared to an earlier period can come handy in various business cases. We may want to compare the Sales or Profit over a region or category of a dimension over every month or year to highlight the percentage difference. We cannot highlight using a table calculation, but this can be done by using a Tableau calculated field which can enable us to clearly distinguish a field by using the Marks color for values which meet the criterion.

For example if we want to highlight the values of Sales for the year 2011 for every State where we had a 20% or more change compared to the previous month, we can do it like below.