It illustrates how the submission dates of national communications have become more harmonised over time as countries have gained experience with reporting, particularly developed countries. It also highlights the limited experience with regular reporting in many developing countries, the majority of which have yet to submit their first biennial update report or third national communication. Over a decade elapsed between the first and second national communications in many developing countries. The transition to a biennial reporting cycle therefore represents a substantial step-up for such countries and significant capacity building efforts will be needed before and after 2020.