Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Experience curves for e-bikes in China (a) and Germany and the Netherlands (b); numbers in parentheses indicate the year of observation; error bars indicate the standard deviation of price data (Data sources: see Table S2 in the Supplementary Material).
