well i dun know, seems low to me still, compared to back then Yoshitsune, every ep was like 20 sth %
The numbers of the ratings today can't really be compared with the numbers from back then, as the demographics/tastes/preferences of the Japanese have changed. You have to remember too that two things have greatly changed since the older versions of this was aired:
1.) The population in Japan has increased greatly
2.) Chances are, the amount of choices on Japanese TV have also greatly increased.
Let's say that this modern version was/is aired in a time where the Japanese have a choice of, say, 50 different channels. The earlier versions were aired when the choice the Japanese would have had would have been, say, perhaps 10 channels. Bottom line, this version undoubtedly faced a lot more competition for veiwers than did the earlier ones. With so much more variety to choose from, you're bound to NOT have as many viewers for this version than was had with the earlier versions. With fewer choices back then, of course the older versions will look like they've "done better" in terms of ratings (at least when you look at the percentages).
The increased population, combined with the increased number of choices of channels/programs will make the averages look like they are smaller. Looking at the actual total number of people who watched (which in this case, adds up to about 10 million people) would be more accurate than looking at the percentages.