Why bimodal? Houses are being built every year. So maybe houses built in 2023 have appreciated 1% more than in 2022, and those have appreciated 1% more than 202

Why bimodal? Houses are being built every year. So maybe houses built in 2023 have appreciated 1% more than in 2022, and those have appreciated 1% more than 2021, and so on, leading to a smooth distribution.