I do not have historical P/B numbers. If anybody has that data...
Here it comes:

BRK - Quarterly Book Value since 2000
BV Q1 Q2 Q3 Q4 BV YTY Year End Price

2000 $38,023 $37,011 $37,810 $38,938 - $71,000
2001 $40,436 $38,240 $38,464 $37,475 -3.9% $75,600
2002 $37,854 $39,444 $40,819 $41,718 10.2% $72,750
2003 $52,575 $45,995 $46,870 $50,484 17.4% $84,250
2004 $55,806 $52,302 $52,455 $55,806 9.5% $87,900
2005 $56,160 $57,213 $58,125 $59,372 6.0% $88,620
2006 $61,878 $62,857 $66,282 $70,277 15.5% $109,990
2007 $71,210 $74,484 $77,475 $78,001 9.9% $141,600
2008 $77,075 $76,176 $77,555 $70,330 -10.9% $96,600
2009 $66,208 $73,812 $81,282 $82,052 14.3% $99,200
2010 $89,378 $86,650 $90,836 $95,433 14.0% $120,450
2011 $97,073 $98,709 $96,901 $99,837 4.4% $114,755
2012 $106,613 $107,356 $111,695 $114,196 12.6% $134,060
2013 $120,520 $122,873 $126,763 $134,986 15.4% $177,900
2014 $138,454 $142,483 $144,580 $146,226 7.7% $226,000
2015 $146,979 $149,743 $151,097 $155,495 6.0% $197,800
2016 $157,350 $160,012 $163,813 $171,565 9.4% $244,121
2017 $178,082 $182,843 $187,450 $211,718 19.0% $297,600
2018 $211,000 $217,654 $228,772 $212,500 0.4% $306,000
2019 $224,950 $233,997 $243,606 $261,417 18.7% $339,590
2020 $229,293 $245,765 $264,323 $287,031 8.9% $347,815
2021 $293,636 $311,276 $316,443 $342,622 16.2% $450,662
2022 $345,469 $314,090 $310,652 $467,000

9.6%
Average