Year	Grassland butterflies (17 species)	Trend line	Lower confidence limits	Upper confidence limits	Confidence limits
1990	116.9740177	100	93.16512842	105.9293315	12.76420305
1991	89.34153628	96.07583866	89.99663554	102.3569876	12.36035209
1992	96.14159717	92.56054512	86.18043692	99.68956687	13.50912994
1993	63.39692341	89.50809421	82.38070462	98.19867917	15.81797455
1994	78.56699304	86.97289117	79.08091001	97.07681754	17.99590753
1995	91.14293759	84.87760842	76.34056054	96.15023902	19.80967848
1996	83.82707257	83.07862158	73.97186667	95.5449301	21.57306344
1997	89.298637	82.11384096	72.57334134	95.47687597	22.90353462
1998	77.73593424	82.10860615	72.21887512	96.07505481	23.85617969
1999	88.13509039	82.30043672	72.04084057	96.36913395	24.32829337
2000	84.26794792	81.92685219	71.52327668	96.62301321	25.09973653
2001	65.06388839	80.75057714	70.21453457	95.49211076	25.27757619
2002	74.78608398	79.12978418	68.06944863	93.70220825	25.63275961
2003	82.41824374	77.19516498	66.19005367	91.4290545	25.23900083
2004	81.25089279	74.74774506	63.72606682	89.21519149	25.48912467
2005	82.21920033	71.8295765	60.57459019	86.30656727	25.73197708
2006	80.12055972	68.93289078	58.00444742	83.4545447	25.45009728
2007	53.97150701	66.54991939	55.05730221	80.95560996	25.89830775
2008	46.28888636	64.51841543	52.69076455	79.39370634	26.70294179
2009	60.88795611	62.57554446	50.14047873	77.77727152	27.63679279
2010	62.14966618	61.0626566	47.97461743	76.11724371	28.14262628
2011	65.83926505	59.98282181	46.4146717	75.28816994	28.87349824
2012	57.3815504	59.16238547	45.26068028	75.32750942	30.06682914
2013	66.51836832	58.67761091	44.25060344	75.05727112	30.80666767
2014	56.25560905	58.60476142	43.48035779	75.66023255	32.17987476
2015	54.35427676	58.95667654	43.349097	76.58744063	33.23834362
2016	58.54477022	59.67786369	43.41957879	77.92810469	34.5085259
2017	62.91451571	60.74208807	43.56535268	79.59209434	36.02674166