Hello. I am working with the NYT COVID-19 data. The data presents two years worth of COVID-19 case and death data. Each month presents the geographic unit's case and death load for that month plus the case and death loads from the previous months ex. (two new cases per month):
```
Date Cases New_Cases
1-20 0 0
2-20 1 1
3-20 3 2
4-20 5 2
5-20 7 2
6-20 9 2
```
Is there a way to generate a variable (New_Cases) to subtract the number of cases from the previous month? For reference, I've included the NYT Github data below:
https://github.com/nytimes/covid-19-...s-counties.csv