Table 20 "Estimated Mean Price Elasticities of Consumption, 1970" is the headline: Direct -1.12 and constrained -1.19; conclusions build the conservation-vs-substitution split (30-35% / 65-70%) from them || "According to the estimates shown in Table 20 this conservation effect is about 30-35 percent of the total mean elasticity of demand." (R-1297 p.58)
Anderson, K.P. (1973b) “Residential Energy Use: An Econometric Analysis.” Rand Corporation Report R-1297-NSF, Santa Monica, California.