Our customer sales are diversified geographically. The following table presents our revenues disaggregated by geography, based on the shipping addresses of our customers: On December 31, 2020, the aggregate transaction price allocated to unsatisfied (or partially unsatisfied) performance obligations related to contracts having an original expected duration in excess of one year was approximately $541 million. We estimate recognition of approximately $412 million of this amount as revenue in 2021 and an additional $129 million in 2022 and thereafter. We receive payment from customers based on a contractual billing schedule and specific performance requirements as established in our contracts. We record billings as accounts receivable when an unconditional right to consideration exists. A contract asset represents revenue recognized in advance of our right to bill the customer under the terms of a contract. A contract liability represents our contractual billings in advance of revenue recognized for a contract. (1) North America represents United States and Canada; Latin America includes Mexico. Contract Balances December 31, 2020 (Amounts in thousands) FPD FCD Total North America(1) $ 1,039,285  $ 429,572  $ 1,468,857  Latin America(1) 191,517  26,393  217,910  Middle East and Africa 359,403  110,539  469,942  Asia Pacific 537,792  270,238  808,030  Europe 545,708  217,687  763,395  $ 2,673,705  $ 1,054,429  $ 3,728,134  December 31, 2019 (Amounts in thousands) FPD FCD Total North America(1) $ 1,085,627  $ 542,182  $ 1,627,809  Latin America(1) 202,247  28,899  231,146  Middle East and Africa 355,937  98,959  454,896  Asia Pacific 499,932  315,886  815,818  Europe 560,702  249,326  810,028  $ 2,704,445  $ 1,235,252  $ 3,939,697  December 31, 2018 (Amounts in thousands) FPD FCD Total North America(1) $ 1,037,637  $ 541,378  $ 1,579,015  Latin America(1) 219,376  22,405  241,781  Middle East and Africa 329,484  138,240  467,724  Asia Pacific 502,559  281,080  783,639  Europe 531,432  232,108  763,540  $ 2,620,488  $ 1,215,211  $ 3,835,699  78