Many datasets of the Open Data BCN portal also have resources published with historical data. What does this mean? Well, not only the current information of the corresponding management system is published, with the indicated periodicity, but also that data of years, quarters or previous months are available to all users, allowing different studies and comparisons to be made. The catalog facilitates the search through the filter 'Historical information: Yes'
Thus, we found annual update datasets, such as among others those of accident rate and demography, quarterly as citizen requests and we highlight the historical datasets of those in which we publish the data with frequency of instant update or every 5 minutes, such as traffic, where you can find data for months since October of 2017, bicing, both the use and the seasons, with data from the month of August and the air quality since June 2018. Others, such as street trees and Tourist housing present quarterly series.