Dec 20 (Reuters) - The Baltic Exchange's main sea freight index declined for a 13th straight session on Friday, weighed down by declining rates across all vessel categories.
* The Baltic index, which tracks rates for capesize, panamax and supramax vessels that ferry dry bulk commodities, decreased 28 points, or 2.4%, to 1,123, its lowest in over six months.
* The index has lost over 17% in the week.
* The capesize index dropped 18 points, or 0.9%, to 1,958 — its lowest since June 18.
* The index fell over 20% this week, marking its third straight weekly fall.
* Average daily earnings for capesizes, which typically transport 170,000-180,000 tonne cargoes including iron ore and coal, slid $124 to $14,451.
* The panamax index declined 64 points, or 5.1%, to 1,201, its lowest since Nov. 28.
* The index has fallen over 18% this week, marking its biggest weekly decline since the beginning of February.
* Average daily earnings for panamaxes, which usually carry coal or grain cargoes of about 60,000 tonnes to 70,000 tonnes, decreased $517 to $9,612.
* The supramax index fell 21 points to 743. (Reporting by Anjishnu Mondal in Bengaluru; Editing by Krishna Chandra Eluri)