## 3 Results and Discussion
### MR Category  
As shown in Table 6. In the northern and southern European countries, achievements in seven MR credits were similar, whereas achievements in one credit were different. In particular, similar high achievements were revealed for MRc2 Construction Waste Management and MRc5 Regional Materials, whereas similar low achievements were revealed for MRc1.1 and MRc1.2 Building Reuse (Maintain Existing Walls, Floors and Roof and Maintain Existing Interior Nonstructural Elements), MRc3 Materials Reuse, MRc6 Rapidly Renewable Materials, and MRc7 Certified Wood. Different achievements were revealed for MRc4 Recycled Content (Sweden's achievement was the best, whereas Finland's achievement was the worst; and Turkey's achievement was the best, whereas Spain's achievement was the worst).  
Thus, only two (that are usually easy for achievement) credits were high-achieving: Waste Management and Regional Materials, whereas seven low-achieving credits were low-achieved, resulting in low MR category achievement (20-30% in northern European countries and 40% in southern European countries). In this respect, it should be noted that MR is a well-known low-achievement category because it is very difficult to reduce virgin building materials and replace them by reusing or recycling materials [8]. Thus, in previous studies concerning the LEED-NC 2009 projects certified in the U.S. and across all the world [7] and the LEED-NC 2009 projects certified in 10 U.S. states [8], a similar low-achieved MR category was reported at 39% [7] and 40-45% [8], respectively. Such rich empirical confidence in the low-achieved MR category requires further attention of LEED experts to low-popular difficult MR credits that represent reusing material options.  
\begin{table}
\begin{tabular}{l c c c c c c c c} \hline \hline \multirow{2}{*}{**Credit**} & \multirow{2}{*}{**Pt**} & \multicolumn{2}{c}{**Finland**} & \multicolumn{1}{c}{**Sweden**} & \multicolumn{1}{c}{**Finland vs. Sweden**} & \multicolumn{1}{c}{**Turkey**} & \multicolumn{1}{c}{**Spain**} & \multicolumn{1}{c}{**Turkey vs. Spain**} \\ \cline{3-8}  & & \multicolumn{2}{c}{**Median \(\pm\) IQR [25-75]**} & \multicolumn{1}{c}{_p_} & \multicolumn{1}{c}{_\(\delta\)_} & \multicolumn{1}{c}{**Median \(\pm\) IQR [25-75]**} & \multicolumn{1}{c}{_p_} & \multicolumn{1}{c}{_\(\delta\)_} \\ \hline MRc1.1 & 3 & 0.0 \(\pm\) 1.5 \({}^{\text{b}}\) & 0.0 \(\pm\) 0.0 \({}^{\text{b}}\) & 0.157 & 0.21 & 0.0 \(\pm\) 0.0 \({}^{\text{b}}\) & 0.0 \(\pm\) 1.5 \({}^{\text{b}}\) & _0.003_ & \(-\)0.23 \\ MRc1.2 & 1 & 0.0 \(\pm\) 0.0 \({}^{\text{b}}\) & 0.0 \(\pm\) 0.0 \({}^{\text{b}}\) & 1.000 & 0.00 & 0.0 \(\pm\) 0.0 \({}^{\text{b}}\) & 0.0 \(\pm\) 0.0 \({}^{\text{b}}\) & 1.000 & 0.01 \\ MRc2 & 2 & 2.0 \(\pm\) 0.8 \({}^{\text{a}}\) & 2.0 \(\pm\) 0.0 \({}^{\text{a}}\) & 0.616 & \(-\)0.09 & 2.0 \(\pm\) 1.0 \({}^{\text{a}}\) & 2.0 \(\pm\) 0.8 \({}^{\text{a}}\) & 0.870 & \(-\)0.03 \\ MRc3 & 2 & 0.0 \(\pm\) 0.0 \({}^{\text{b}}\) & 0.0 \(\pm\) 0.0 \({}^{\text{b}}\) & 1.000 & 0.00 & 0.0 \(\pm\) 0.0 \({}^{\text{b}}\) & 0.0 \(\pm\) 0.0 \({}^{\text{b}}\) & 1.000 & \(-\)0.02 \\ MRc4 & 2 & 0.0 \(\pm\) 0.0 \({}^{\text{c}}\) & 1.0 \(\pm\) 1.0 \({}^{\text{c}}\) & **0.005** & \(-\)0.50 & 2.0 \(\pm\) 0.0 \({}^{\text{c}}\) & 1.0 \(\pm\) 1.8 \({}^{\text{c}}\) & **0.001** & 0.42 \\ MRc5 & 2 & 2.0 \(\pm\) 2.0 \({}^{\text{a}}\) & 2.0 \(\pm\) 2.0 \({}^{\text{a}}\) & 0.872 & 0.04 & 2.0 \(\pm\) 0.0 \({}^{\text{a}}\) & 2.0 \(\pm\) 0.0 \({}^{\text{a}}\) & 0.141 & 0.11 \\ \hline \hline \end{tabular}
\end{table}
Table 6: MR achievement: Northern European countries vs southern European countries.  
Figure 1: The EAc1 Optimize Energy Performance: Northern European countries vs. southern European countries. A red dashed line refers to the maximum possible points.