Here are plots as of 2020-03-27 of active cases of COVID-19 (coronavirus disease 2019) over time, including presumptive positive cases. The data is from this github repo maintained by Johns Hopkins University Center for Systems Science and Engineering.

Y axis:

The dotted lines are 3-day predictions made by regressing an exponential fit over data from the last 7 days. For instance for the US, the regression is

\[ \text{active cases} = 99207 \cdot 2^{t / 3.3\text{ days}}, \]

predicting that active US cases will double in 3.3 days.

But we can slow it down by taking precautions. How to protect yourself (US CDC).