For a single pair, the minimum possible link bitrate is 192 kbit/s (3 x 64 kbit/s) and the maximum bitrate is 5.7 Mbit/s (89 x 64 kbit/s).
The throughput of a 2BASE-TL link is lower than the link's bitrate by an average 5%, due to 64/65-octet encoding and PAF overhead, both factors depend on packet size [REF].