350 PONTIFICIAE ACADEMIAE SCIENTIARVM SCRIPTA VARIA - 28 
If it is now assumed that the amortisation periods for equip- 
ment and structures are respectively 5 and 20 years (1), and if 
it is further assumed that the average production period for 
equipment goods is (Hypothesis H”) 
® = 4.23 
‘his leads to assessing at 10 and 25 years respectively the ap- 
proximate length of the amortisation period of the primary 
inputs incorporated in equipment and structural assets. 
If it is assumed that all investment consists of durable 
goods, and maintenance and repair outlays are abstracted, 
the position can be summarised as in Table 10 below (in $ bil- 
lion) on the basis of the estimates in § 333-6 (2). 
TABLE 10 
(nventories 
Zquipment 
Structures 
- + 
. . 
Total 
Equipment and 
Structures . 
[22.3 
340.8 
726.6 
[190.7 
1077.4 | 
RA 
199.5 
34.1 
20.5 
262.1 
63.6 ! 
C/Ra 
0.61 
Io 
26 
4.56 
16.04 | 
C | Re: 
n % in % 
10.2 
28.4 
61.4 
75-9 
13.0 
II.1 
TON 
ra 
80.8 | 
24.1 
() These are the figures used by various fiscal administrative agencies. 
(?) The values of R, for equipment and structural assets are obtained 
y dividing the figures in the first column into those in the third. The 
?, figures for inventories are then obtained bv difference 
263. T — 34.1 — 20.5 = 100.4 
11] Allais - pag. 154