The 2015 on-time average for containerships hit a record high of 73 percent, though a wide gap remains between the best and worst performers, according to Drewry's latest analysis.

Despite a mild deterioration in the final three months of the year, the year-long reliability average for all trades covered represented a marked improvement on 2014.

"On-time reliability for the 12-month period for all trades reached 73 percent, against an average of just 59 percent in 2014," said Drewry, according to Lloyd's Loading List.

The analyst said explaining the marked improvement in service levels in 2015 was difficult, but surmised that it was a "a reflection of the operational improvements brought about by the new, enlarged carrier alliances, and that carriers in general are belatedly recognising the importance of reliability in terms of marketing and customer retention." 

In 2015, the carrier with the highest overall on-time performance was Maersk Line with a 12-month average of 81 percent. Mediterranean Shipping Company was the worst performer, scoring 58.4 percent.