US CPI data quality is deteriorating: The Bureau of Labor Statistics (BLS) calculates CPI inflation by gathering ~90,000 monthly price quotes across 200 product and service categories. There are hundreds of field collectors tracking these prices in 75 urban areas nationwide. However, when price data is unavailable, BLS uses estimates, which typically average ~10% of all data points. Most recently, in May, the share of estimates jumped to ~30%. In other words, nearly 1/3 of the prices within the CPI were simply "estimated" last month. What is happening here?