Although not all of the projects have been completed (especially
in the case of the second-generation key projects), it was possible
to draw tentative conclusions on the basis of the data available.
Our assessment of the development of office rental rates was based
on data on all new rental contracts for new and existing offices.
These showed considerable fluctuation over the years, as they were
based on relatively few large transactions. This was partly mitigated
by using a 3-year moving average. A correction factor was
also applied to account for differences in regional development.
It was not possible to use a weighted average, as the office surface
areas involved in each transaction were not known.