{"Year":1675,"speed":220000}
{"Year":1729,"speed":301000}
{"Year":1849,"speed":315000}
{"Year":1862,"speed":298000,"error":500}
{"Year":1907,"speed":299710,"error":30}
{"Year":1926,"speed":299796,"error":4}
{"Year":1950,"speed":299792.5,"error":3}
{"Year":1958,"speed":299792.5,"error":0.1}
{"Year":1972,"speed":299792.4562,"error":0.00111}