How do I show a 100% variance percent when the previous period is 0

I want to show 100% for the variance percent when the previous figure is 0. I am using the formula: eval(current period - previous period) / previous period.

In the 2 images, the first column (most left) is the current period. the second column is the previous period and the third column is the variance.

The fourth column is my current formula and the last column (most right) is the desired figure in image 2. How do I write a conditional formula that indicates when the previous value is 0 and the current period value is #, then populate positive 100% increase? Thank you in advance!

image 1