Determining the percentage of space that has been discovered is a challenging task due to the vastness of the universe and the limitations of current technology. The observable universe, which is the portion of the universe we can currently observe, is estimated to have a radius of about 46.5 billion light-years. However, even the observable universe is a relatively small fraction of the entire universe, as it is believed to be much larger and possibly infinite.
Considering the observable universe, it's important to note that our knowledge is limited to what we have been able to observe and study. Scientists have made remarkable progress in mapping and understanding the cosmos, but there are still vast regions of space that remain unexplored or poorly understood. Moreover, the universe is continually expanding, making it even more challenging to determine the exact extent of what has been discovered.
In summary, it is difficult to quantify the exact percentage of space that has been explored or discovered. Our understanding of the universe is an ongoing process, and there is still much more to learn and explore.