That is an incredibly difficult thing to measure, so I can provide the general consensus of; not nearly as much as we'd like.

War crimes - There are still war crimes going on, as horrific as they were in WWII. Stopping war crimes, and crimes against humanity during war is one of the fundamental focuses of the Geneva Convention, and the UN. Case examples being Syria, where chemical weapons have been used. Rwanda, where there was a mass-genocide, and various crimes against humanity. Yugoslavia, where ethnic-cleansing was conducted on an enormous scale. I could go on, but the point is simply that we have not at all seriously reduced crimes against humanity in war.

Article 4 of the Universal Declaration of Human Rights - No, we have not stopped slavery. The worst cases nowadays is in sex trafficking.

https://www.unodc.org/unodc/en/human-trafficking/global-report-on-trafficking-in-persons.html

This is the UNODC 2013 report on human trafficking.

Article 18 of the Universal Declaration of Human Rights - This one, in some cases, has slightly improved. Though one need take a look at any trials in modern Islamic nations (Saudi-Arabia, Sudan), to see that apostasy is still a crime punishable by death.

One can simply look through the charter, and see a situation where these are not upheld. I have provided a few examples of this, and would simply say that occurrences of these crimes have not substantially dropped to the level we would like to see.