News Flash - Recessions reduce GDP growth

All of the projections I have seen from the CBO or Social Security assume that nominal GDP will increase about 4% forever, like clockwork.  Here is a chart of just the next 10 years.

2019	21,485	4.40%
2020	22,523	4.83%
2021	23,558	4.60%
2022	24,616	4.49%
2023	25,735	4.55%
2024	26,907	4.55%
2025	28,109	4.47%
2026	29,349	4.41%
2027	30,637	4.39%
2028	31,972	4.36%
2029	33,363	4.35%
2030	34,800	4.31%

However, nominal GDP growth slows down or even turns negative during a recession. Look at 2008 and 2009.

Year	Nominal GDP	Growth
2000	10,252
2001	10,582	3.22%
2002	10,936	3.35%
2003	11,458	4.77%
2004	12,214	6.60%
2005	13,037	6.74%
2006	13,815	5.97%
2007	14,452	4.61%
2008	14,713	1.81%
2009	14,449	-1.79%
2010	14,992	3.76%
2011	15,543	3.68%
2012	16,197	4.21%
2013	16,785	3.63%
2014	17,527	4.42%
2015	18,225	3.98%
2016	18,715	2.69%
2017	19,519	4.30%
2018	20,580	5.44%

Source https://www.thebalance.com/us-gdp-by-year-3305543

Of course we don't know exactly when recessions are going to hit and the time between them keeps getting longer, but I think every ten years going forward you should include a recession in the calculations.

Question: what effect does a recession have on government revenues (taxes)?