One option to compare the table values to other versions of itself is by JOIN
ing the table to itself as the following shows.
Using the LEFT JOIN method allows the possibility to review back to the earliest records, and using the IsNull operator will compensate for the records that do not exist.
SELECT i.ELEMENTO, i.VALOR
, ValorPrior = IsNull(j.Valor, 0)
, ValorChange= i.Valor - IsNull(j.Valor, 0)
FROM Operacion.Informe AS i
LEFT JOIN Operacion.Informe AS j ON Year(i.ELEMENTO) = 1 + Year(j.ELEMENTO)WHERE clauses have been removed so that you can review how this is working, and then you can add them back in as needed