Just wanted to share an experience of letting a folder zipped through two different extensions.
After making a folder zipped, actual folder, having size on disk 18.7 MB (19,673,088 bytes), following are the results of both zip and 7z experiments.
Zip Through Zip Extension
While zipping the 18.7 MB folder into zip extension, the zip file size comes into 12.3 MB (12,931,072 bytes)
Zip Through 7z Extension
Using 7z extension, through software 7-zip, the file came into just 3.00 MB (3,149,824 bytes)
Great experience, good to know, better to share.