# Introduction

Using the Ratio feature, with one click you can create a ratio expressing the relation of a series of your choice to one of the following, predefined indicators:

• Per Capita -
It divides the selected series by the population of this series’ Region.
• Per GDP -
It divides the series by the GDP value, in current prices, of this series’ Region.
• Per GDP Percent -
It divides the series by the GDP value, in current prices, of this series’ Region and sets the result as a percentage.
• Per CPI -
It deflates the selected series by the headline CPI of this series’ Region.
• Per CPI Core -
It deflates the selected series by the core CPI of this series’ Region.
• Per CPI Harmonized -
It deflates the selected series by the harmonized CPI of this series’ Region.
• DeAnnualRate -
It divides the series by the observation count per year and sets the result as a Flow series.

Per CPI, Per CPI Core and Per CPI Harmonized options are available in Macrobond 1.21 and later.

# Benefits of using Ratios

Using the Ratio feature has several advantages:

1. It can happen that sources do not calculate such ratios themselves (example: Current Account as % of GDP). Therefore, such series are not available in Macrobond and need to be calculated by you. Ratios allow you to perform this calculation with one click.
2. Ratios can be performed on multiple series at once.
3. You save a lot of time on deciding on the best possible combination of the underlying series. # Frequency conversions

Like any Macrobond document, all series used in the Ratio will be expressed in the same frequency. By default, the document will use the frequency of the series of your choice for which you would like to create a Ratio.

For example, if you want to calculate a ratio of GDP Per Capita with quarterly frequency, you can select a quarterly GDP flow series and divide it by an annual population stock series (using the PerCapita Ratio).

By default, Flows series are converted to a higher frequency by aggregating their data points, and stock series by interpolation.

# Missing Data

Sometimes, when selected series have different frequencies or one of them is lagging towards the other, the application extends the shorter series by using the ExtendLastYoYForecast formula function.