According to the default settings, empty and invalid surveys or units are not included in the analysis. Such units have special statuses, ranging from 0 to 4, and may be recognized by a large number of missing values or they can also be empty surveys, where respondents did not answer any question (e.g. lurkers).
If you wish to include every survey in your analysis, which is rarely the case, you can specify this in the 'DATA' or 'ANALYSE' tab choosing 'All units' above the data table. If you want the data for all units to be displayed in both tabs, i.e. in the 'DATA' tab as well as in the 'ANALYSE' tab, the 'All units' option must be selected in both tabs.
The database and analysis are being updated regularly (more on data updates).