In this publication, as a tool for presenting statistical data, an MS Excel spreadsheet was used, which contains information in the form of absolute and relative (indicators) numbers.

Statistics most often and most commonly uses numbers to describe the studied populations or phenomena. The description may be aimed at presenting the **number** (size), **structure** or **indices** of the population or phenomena.

The collective numerical characteristics of the statistical population include indicators.

The indicator is a quotient of two quantities corresponding to the components of a given population or representing the characteristics of two different populations, or relating to the same population, but in different periods or moments.

There are three main types of indicators:

- indicators of structure
- indicators of intensity,
- indicators of dynamics.

**Indicators of structure,** also known as structural numbers, determine the ratio of a certain size concerning a part of the statistical population to that size concerning the entire population.

**An indicator or measure of intensity ** determines the ratio of quantities characterising two different populations or statistical phenomena related to each other in some causal or logical way.

**Indicators of dynamics ** express the ratio between the numbers characterising a certain quantity in two different periods or moments of time. They are used to study dynamic series, i.e. changes that occur in statistical populations over a period of time.

There are two basic measures of the dynamics of a statistical population: **absolute increase and relative increase**.

**The absolute increase** is the difference between the values of the variable in consecutive periods (e.g. in consecutive years, months or days).

**The relative increase ** is the ratio of the absolute increase to the value of the variable from the previous period. If this relative increase is multiplied by 100, we will get a **percentage increase**.

Przyrost absolutny i przyrost względny mogą przybierać wartości dodatnie, ujemne, względnie mogą być równe zero.

**Indexes** are the most commonly used measure of dynamics. The index is the ratio of the variable value from different periods to the value of the same variable from the determined comparative period.

Relative numbers were usually calculated based on absolute data expressed with greater accuracy than those given in the spreadsheets.

When calculating data per capita (1000 population, etc.) as of the end of the year (e.g. employment, public library collection), the population was assumed as of 31 December, and when calculating data characterising the size of the phenomenon during the year (e.g. vital statistics, dwellings completed) – as of 30 June.

Automatic rounding of numbers in some cases could cause minor differences in sums of data at higher level of aggregation.

Methods for calculating the indicators included in the publication.