Fig. 3From: Assessment of technological level of stem cell research using principal component analysisThe obsolescence rate curve. The curve of obsolescence rate was created given the calculated CHL (9.286 years) which indicates that 50 % of the residual value would be decreased by every 9.286 years. The obsolescence rate at certain time point can be calculated via subtracting residual value out of 100 % (see Table 13 for the residual value)Back to article page