Spatial-Temporal Evolution Characteristics and Countermeasures of Urban Innovation Space Distribution: An Empirical Study Based on Data of Nanjing High-Tech Enterprises

Table 2

Nearest neighbor index of high-tech enterprises identified in Nanjing.

Variables	2008–2010	2011–2013	2014–2016	2017–2019
NNI	0.358	0.329	0.304	0.215

The NNI is significant at the level of 10%, 5%, and 1%.