What do you call the ratio of positive to negative samples? I am working with a binary classifier and I want to express the "balance" or "skewness" of the training data using a metric. 

I want to reflect this ratio in a report, like this:

Accuracy: 80%
Recall: 78%
Precision: 62%
*The Ratio of Positive to Negative Samples*: 62%


I feel like there's probably a standard name for the metric expressing "The Ratio of Positive to Negative Samples".

My main question is: What is the name of this metric? 

(This question assumes that there is a standard name for this metric.)



Extra Information:

Here are some example values for the metric and their interpretations:

1.0 = The sample (of training data) is balanced.
0.5 = There are twice as many negative samples as positive samples.
2.0 = There are twice as many positive samples as negative samples.


My secondary question is: Is there another metric that can be used to form similarly meaningful interpretations?
You can use class ratio / sample class ratio. Which will make it more intuitive for any reader while going through the details.

As its not used for model performance analysis hence I think we don’t have a metric name for this.