The image below shows a number of average HD video bitrates from the past few weeks. All programming is HD (nothing being upscaled). 12 different channels are represented across 3 satellites: 61.5W, 72.7W, and 110W. All samples were at least 60 minutes in duration.

As HDRoberts mentioned, the bitrate is going to vary under different conditions. I wouldn't say that 5-6 Mbps is common anymore, but it does still happen under some conditions.
You're looking at transponders supporting about 41 Mbps typically having at least 8 HD channels for the satellites shown above. Subtract about 3 Mbps for 8x 384 Kbps audio streams, plus say 1 Mbps for the NULL stream (although it can be quite a bit higher on average on some transponders), plus another 1 Mbps for the normal data streams and you have 36 Mbps left. With that, you're averaging about 4.5 Mbps video per channel with 8 channels/transponder, about 4 Mbps with 9 channels, and 3.6 Mbps with 10 channels (or 9 channels plus a bunch of extra data streams, like transponder 32 on 61.5W).