The indicator Circular Material Use Rate (CMU), which belongs to the Circular Economy Indicators, is the main variable under study. CMU measures the percentage share of material recycled and fed back into the economy, hence saving removal of primary raw materials in total material use. In other words, the Circularity Rate is the ratio of the circular use of materials to the overall material use. A higher CMU shows more secondary materials substituting for primary raw materials. Using correlation and multiple regression analysis, CMU in EU27_2020 countries in 2021 (CMU_2021) is analyzed and explained by three independent variables, two environmental and one economical, which are shortly defined as follows: 1 - Resource Productivity (RP_2021), which is important circular economy, and environmental indicator, which is defined as the efficiency of natural resources used to produce goods and services in an economy and is expressed in Euro per kg; 2 - Gross domestic expenditure on Research and Development (R&D) (shortly, GERD_2021), which is a percent of Gross Domestic Product (GDP); and 3 - General government expenditure for environmental protection, as a percent of GDP (ENVIR%GPD_2021). Exploratory data analysis of all four included variables for EU27_2020 countries in 2021 shows high ranges and positive skewness for all the distributions but did not show any serious outlier in the data. Trend analysis and forecasting were performed, as well. It was found that CMU_2021 correlates positively and moderately strongly to RP_2021, with a correlation of 0.638. Between CMU_2021 and GERD_2021 a positive and rather weak correlation of 0.389 appeared, but with ENVIR%GDP_2021 only a moderately weak positive correlation of 0.482 was found. For 27 countries in 2021, a multiple linear regression model was built based on Mallows’ Cp metric in the All Possible Regressions approach and estimated by the Ordinary Least Squares method. Each of the regressors showed a statistically significant positive impact on CMU while having the remaining indicators fixed in a model. A hierarchical cluster analysis of the observed 27 countries resulted in three clusters of countries, respecting all four considered variables, economic and environmental. In 2021 an economically rich country, the Netherlands, was ranked at the top for environmental care variables, CMU and RP, and was followed by Belgium, France, and Italy, and these four countries comprised a Cluster of circular economy most developed countries. The next Cluster of circular economy developed countries, included five members, Denmark, Austria, Germany, Sweden, and Finland. In 2021, Croatia had the highest ENVIR%GPD_2021, 1.5 %, but appeared to be in a Cluster of circular economy less developed and developing countries, which has 18 members in total. Surprisingly, in the same Cluster, there are rich Luxembourg and Ireland, because of having high values for RP_2021 only, and poor data for the remaining three variables.
