**Abbreviations**

ACF: autocorrelation Function; AIDS: acquired immunodeficiency syndrome; BHB: benchmarked hierarchical Bayesian; CSA: Central Statistics Agency; DHS: Demographic and Health Survey; EDHS: Ethiopia DHS; EMDHS: Ethiopian Mini DHS; EPHI: Ethiopian Public Health Institute; FMoH: Federal Ministry of Health; GDP: gross domestic product; HB: hierarchical Bayesian; HH: household; IPUMS: Integrated Public Use Microdata Series; MCMC: Markov chain Monte Carlo; PMSE: posterior mean squared error; RBHB: ratio-benchmarked hierarchical Bayesian; SA1: small area one; SA2: small area two; SAE: small area estimation; SD: standard deviation; SNNP: Southern Nations, Nationalities and People; SNNPR: Southern Nations Nationalities and People's Region; U5: under five; WHO: World Health Organization.
