Kansas:
2000: 2,694,000
2010: 2,859,000
2017: 2,913,000
These are all consistently increasing year after year:
Nebraska, Oklahoma, Arkansas, Indiana, Missouri, Iowa, Minnesota, Ohio.
Illinois is hit or miss, however it's up a million people over 20 years.
Michigan is the only one that has particularly struggled. Its population remains above where it was 20 years ago; it's about 50k people (~0.5%) below its 2004 record high.
Connecticut is definitely struggling, they've seen zero growth over seven or eight years, and comparatively little growth over 40 years despite being an affluent state.