Table 2 Annual phosphate deposition from 1998 to 2017 (kg P km^{−2} a^{−1}) estimated (a) as the sum of direct measurements, (b) sum of measured values plus 0.53 µmol P l^{−1} as median for all rain samples, where values are missing and (c) all rain samples with median concentration of 0.53 µmol P l^{−1}