Both can include forward-looking projections in addition to historical trends. Variations of this NDC type include emission reductions from a base year (e.g. a 20% reduction from 1990 levels), emission reductions to a specified emission level (e.g. 300 MtC02-eq) or achievement of carbon neutrality by a given date (i.e. the specified net emissions level is zero). Some countries had previously expressed goals for carbon neutrality under the Cancun Agreements (Maldives and Costa Rica).