Revenue allocated to remaining performance obligations represents contracted revenue that has not yet been recognized (“contracted not recognized revenue”), which includes both unearned revenue and revenue that will be invoiced and recognized in future periods. Deferred revenue recognized in the three months ended March 31, 2020 and 2019 were $42.7 million and $40.0 million, respectively. Changes in unearned revenue were as follows:

Changes in unearned revenue were as follows:

The Company has no material contracted, but not recognized revenue as of March 31, 2020 or December 31, 2019.

At March 31, 2020 and December 31, 2019, the Company had long-term unearned revenue of $14.0 million and $13.7 million, respectively. Unearned short-term revenue is recognized over the next 12-month period. The majority of unearned long-term revenue is recognized over a period of five years or less with immaterial amounts recognized through 2029.